diff --git a/libs/surfaces/cc121/cc121.cc b/libs/surfaces/cc121/cc121.cc
index 0cc6fc2254..386a46cc20 100644
--- a/libs/surfaces/cc121/cc121.cc
+++ b/libs/surfaces/cc121/cc121.cc
@@ -105,13 +105,13 @@ CC121::CC121 (Session& s)
 	_input_bundle->add_channel (
 		"",
 		ARDOUR::DataType::MIDI,
-		_session->engine().make_port_name_non_relative (inp->name())
+		make_port_name_non_relative (inp->name())
 		);
 
 	_output_bundle->add_channel (
 		"",
 		ARDOUR::DataType::MIDI,
-		_session->engine().make_port_name_non_relative (outp->name())
+		make_port_name_non_relative (outp->name())
 		);
 
 
@@ -805,8 +805,8 @@ CC121::connection_handler (boost::weak_ptr<ARDOUR::Port>, std::string name1, boo
 		return false;
 	}
 
-	string ni = ARDOUR::AudioEngine::instance()->make_port_name_non_relative (boost::shared_ptr<ARDOUR::Port>(_input_port)->name());
-	string no = ARDOUR::AudioEngine::instance()->make_port_name_non_relative (boost::shared_ptr<ARDOUR::Port>(_output_port)->name());
+	string ni = make_port_name_non_relative (boost::shared_ptr<ARDOUR::Port>(_input_port)->name());
+	string no = make_port_name_non_relative (boost::shared_ptr<ARDOUR::Port>(_output_port)->name());
 
 	if (ni == name1 || ni == name2) {
 		if (yn) {
diff --git a/libs/surfaces/control_protocol/basic_ui.cc b/libs/surfaces/control_protocol/basic_ui.cc
index 6af4d80427..c574c0b0f8 100644
--- a/libs/surfaces/control_protocol/basic_ui.cc
+++ b/libs/surfaces/control_protocol/basic_ui.cc
@@ -28,6 +28,7 @@
 
 #include "temporal/tempo.h"
 
+#include "ardour/audioengine.h"
 #include "ardour/session.h"
 #include "ardour/location.h"
 #include "ardour/tempo.h"
@@ -788,3 +789,8 @@ BasicUI::goto_nth_marker (int n)
 	}
 }
 
+std::string
+BasicUI::make_port_name_non_relative (const std::string& name) const
+{
+	return _session->engine ().make_port_name_non_relative (name);
+}
diff --git a/libs/surfaces/control_protocol/control_protocol/basic_ui.h b/libs/surfaces/control_protocol/control_protocol/basic_ui.h
index b2a6506fc5..1fe216697c 100644
--- a/libs/surfaces/control_protocol/control_protocol/basic_ui.h
+++ b/libs/surfaces/control_protocol/control_protocol/basic_ui.h
@@ -154,6 +154,10 @@ class LIBCONTROLCP_API BasicUI {
 	bool rewind_button_onoff() const;
 	bool loop_button_onoff() const;
 
+	/* Naming */
+
+	std::string make_port_name_non_relative (const std::string& name) const;
+
   protected:
 	Session* _session;
 };
diff --git a/libs/surfaces/faderport/faderport.cc b/libs/surfaces/faderport/faderport.cc
index fcc0097e8a..7a1f596a5b 100644
--- a/libs/surfaces/faderport/faderport.cc
+++ b/libs/surfaces/faderport/faderport.cc
@@ -99,13 +99,13 @@ FaderPort::FaderPort (Session& s)
 	_input_bundle->add_channel (
 		"",
 		ARDOUR::DataType::MIDI,
-		_session->engine().make_port_name_non_relative (inp->name())
+		make_port_name_non_relative (inp->name())
 		);
 
 	_output_bundle->add_channel (
 		"",
 		ARDOUR::DataType::MIDI,
-		_session->engine().make_port_name_non_relative (outp->name())
+		make_port_name_non_relative (outp->name())
 		);
 
 	/* Catch port connections and disconnections */
@@ -837,8 +837,8 @@ FaderPort::connection_handler (boost::weak_ptr<ARDOUR::Port>, std::string name1,
 		return false;
 	}
 
-	string ni = ARDOUR::AudioEngine::instance()->make_port_name_non_relative (boost::shared_ptr<ARDOUR::Port>(_input_port)->name());
-	string no = ARDOUR::AudioEngine::instance()->make_port_name_non_relative (boost::shared_ptr<ARDOUR::Port>(_output_port)->name());
+	string ni = make_port_name_non_relative (boost::shared_ptr<ARDOUR::Port>(_input_port)->name());
+	string no = make_port_name_non_relative (boost::shared_ptr<ARDOUR::Port>(_output_port)->name());
 
 	if (ni == name1 || ni == name2) {
 		if (yn) {
diff --git a/libs/surfaces/faderport8/faderport8.cc b/libs/surfaces/faderport8/faderport8.cc
index 9808aa1841..1190d76ecb 100644
--- a/libs/surfaces/faderport8/faderport8.cc
+++ b/libs/surfaces/faderport8/faderport8.cc
@@ -162,13 +162,13 @@ FaderPort8::FaderPort8 (Session& s)
 	_input_bundle->add_channel (
 		"",
 		ARDOUR::DataType::MIDI,
-		_session->engine().make_port_name_non_relative (inp->name())
+		make_port_name_non_relative (inp->name())
 		);
 
 	_output_bundle->add_channel (
 		"",
 		ARDOUR::DataType::MIDI,
-		_session->engine().make_port_name_non_relative (outp->name())
+		make_port_name_non_relative (outp->name())
 		);
 
 	ARDOUR::AudioEngine::instance()->PortConnectedOrDisconnected.connect (port_connections, MISSING_INVALIDATOR, boost::bind (&FaderPort8::connection_handler, this, _2, _4), this);
@@ -428,8 +428,8 @@ FaderPort8::connection_handler (std::string name1, std::string name2)
 		return false;
 	}
 
-	string ni = ARDOUR::AudioEngine::instance()->make_port_name_non_relative (boost::shared_ptr<ARDOUR::Port>(_input_port)->name());
-	string no = ARDOUR::AudioEngine::instance()->make_port_name_non_relative (boost::shared_ptr<ARDOUR::Port>(_output_port)->name());
+	string ni = make_port_name_non_relative (boost::shared_ptr<ARDOUR::Port>(_input_port)->name());
+	string no = make_port_name_non_relative (boost::shared_ptr<ARDOUR::Port>(_output_port)->name());
 
 	if (ni == name1 || ni == name2) {
 		DEBUG_TRACE (DEBUG::FaderPort8, string_compose ("Connection notify %1 and %2\n", name1, name2));
diff --git a/libs/surfaces/generic_midi/generic_midi_control_protocol.cc b/libs/surfaces/generic_midi/generic_midi_control_protocol.cc
index db991c8397..f51864f727 100644
--- a/libs/surfaces/generic_midi/generic_midi_control_protocol.cc
+++ b/libs/surfaces/generic_midi/generic_midi_control_protocol.cc
@@ -99,13 +99,13 @@ GenericMidiControlProtocol::GenericMidiControlProtocol (Session& s)
 	_input_bundle->add_channel (
 		"",
 		ARDOUR::DataType::MIDI,
-		_session->engine().make_port_name_non_relative (inp->name())
+		make_port_name_non_relative (inp->name())
 		);
 
 	_output_bundle->add_channel (
 		"",
 		ARDOUR::DataType::MIDI,
-		_session->engine().make_port_name_non_relative (outp->name())
+		make_port_name_non_relative (outp->name())
 		);
 
 	_session->BundleAddedOrRemoved ();
@@ -1559,8 +1559,8 @@ GenericMidiControlProtocol::connection_handler (boost::weak_ptr<ARDOUR::Port>, s
 
 	DEBUG_TRACE (DEBUG::GenericMidi, string_compose ("connection change: %1 and %2 connected ? %3\n", name1, name2, yn));
 
-	string ni = ARDOUR::AudioEngine::instance()->make_port_name_non_relative (boost::shared_ptr<ARDOUR::Port>(_input_port)->name());
-	string no = ARDOUR::AudioEngine::instance()->make_port_name_non_relative (boost::shared_ptr<ARDOUR::Port>(_output_port)->name());
+	string ni = make_port_name_non_relative (boost::shared_ptr<ARDOUR::Port>(_input_port)->name());
+	string no = make_port_name_non_relative (boost::shared_ptr<ARDOUR::Port>(_output_port)->name());
 
 	if (ni == name1 || ni == name2) {
 		if (yn) {
diff --git a/libs/surfaces/launch_control_xl/launch_control_xl.cc b/libs/surfaces/launch_control_xl/launch_control_xl.cc
index 407ce85ba5..49c7c1d835 100644
--- a/libs/surfaces/launch_control_xl/launch_control_xl.cc
+++ b/libs/surfaces/launch_control_xl/launch_control_xl.cc
@@ -831,8 +831,8 @@ LaunchControlXL::connection_handler (boost::weak_ptr<ARDOUR::Port>, std::string
 		return false;
 	}
 
-	string ni = ARDOUR::AudioEngine::instance()->make_port_name_non_relative (boost::shared_ptr<ARDOUR::Port>(_async_in)->name());
-	string no = ARDOUR::AudioEngine::instance()->make_port_name_non_relative (boost::shared_ptr<ARDOUR::Port>(_async_out)->name());
+	string ni = make_port_name_non_relative (boost::shared_ptr<ARDOUR::Port>(_async_in)->name());
+	string no = make_port_name_non_relative (boost::shared_ptr<ARDOUR::Port>(_async_out)->name());
 
 	if (ni == name1 || ni == name2) {
 		if (yn) {
diff --git a/libs/surfaces/mackie/mackie_control_protocol.cc b/libs/surfaces/mackie/mackie_control_protocol.cc
index 987909107f..433fba954b 100644
--- a/libs/surfaces/mackie/mackie_control_protocol.cc
+++ b/libs/surfaces/mackie/mackie_control_protocol.cc
@@ -927,13 +927,13 @@ MackieControlProtocol::create_surfaces ()
 			_input_bundle->add_channel (
 				"",
 				ARDOUR::DataType::MIDI,
-				_session->engine().make_port_name_non_relative (surface->port().input_port().name())
+				make_port_name_non_relative (surface->port().input_port().name())
 				);
 
 			_output_bundle->add_channel (
 				"",
 				ARDOUR::DataType::MIDI,
-				_session->engine().make_port_name_non_relative (surface->port().output_port().name())
+				make_port_name_non_relative (surface->port().output_port().name())
 				);
 		}
 
diff --git a/libs/surfaces/mackie/surface.cc b/libs/surfaces/mackie/surface.cc
index ba993e7f0b..48db725bd6 100644
--- a/libs/surfaces/mackie/surface.cc
+++ b/libs/surfaces/mackie/surface.cc
@@ -210,8 +210,8 @@ Surface::connection_handler (boost::weak_ptr<ARDOUR::Port>, std::string name1, b
 		return false;
 	}
 
-	string ni = ARDOUR::AudioEngine::instance()->make_port_name_non_relative (_port->input_name());
-	string no = ARDOUR::AudioEngine::instance()->make_port_name_non_relative (_port->output_name());
+	string ni = _mcp.make_port_name_non_relative (_port->input_name());
+	string no = _mcp.make_port_name_non_relative (_port->output_name());
 
 	if (ni == name1 || ni == name2) {
 		if (yn) {
diff --git a/libs/surfaces/push2/push2.cc b/libs/surfaces/push2/push2.cc
index 4c81325068..c551093414 100644
--- a/libs/surfaces/push2/push2.cc
+++ b/libs/surfaces/push2/push2.cc
@@ -266,7 +266,7 @@ Push2::ports_acquire ()
 		_output_bundle->add_channel (
 			shadow_port->name(),
 			ARDOUR::DataType::MIDI,
-			_session->engine().make_port_name_non_relative (shadow_port->name())
+			make_port_name_non_relative (shadow_port->name())
 			);
 	}
 
@@ -1209,8 +1209,8 @@ Push2::connection_handler (boost::weak_ptr<ARDOUR::Port>, std::string name1, boo
 		return false;
 	}
 
-	string ni = ARDOUR::AudioEngine::instance()->make_port_name_non_relative (boost::shared_ptr<ARDOUR::Port>(_async_in)->name());
-	string no = ARDOUR::AudioEngine::instance()->make_port_name_non_relative (boost::shared_ptr<ARDOUR::Port>(_async_out)->name());
+	string ni = make_port_name_non_relative (boost::shared_ptr<ARDOUR::Port>(_async_in)->name());
+	string no = make_port_name_non_relative (boost::shared_ptr<ARDOUR::Port>(_async_out)->name());
 
 	if (ni == name1 || ni == name2) {
 		if (yn) {
diff --git a/libs/surfaces/us2400/surface.cc b/libs/surfaces/us2400/surface.cc
index a2015d0935..11acbb7be8 100644
--- a/libs/surfaces/us2400/surface.cc
+++ b/libs/surfaces/us2400/surface.cc
@@ -169,8 +169,8 @@ Surface::connection_handler (boost::weak_ptr<ARDOUR::Port>, std::string name1, b
 		return false;
 	}
 
-	string ni = ARDOUR::AudioEngine::instance()->make_port_name_non_relative (_port->input_name());
-	string no = ARDOUR::AudioEngine::instance()->make_port_name_non_relative (_port->output_name());
+	string ni = _mcp.make_port_name_non_relative (_port->input_name());
+	string no = _mcp.make_port_name_non_relative (_port->output_name());
 
 	if (ni == name1 || ni == name2) {
 		if (yn) {
diff --git a/libs/surfaces/us2400/us2400_control_protocol.cc b/libs/surfaces/us2400/us2400_control_protocol.cc
index e523177a16..6671fa5d6d 100644
--- a/libs/surfaces/us2400/us2400_control_protocol.cc
+++ b/libs/surfaces/us2400/us2400_control_protocol.cc
@@ -794,13 +794,13 @@ US2400Protocol::create_surfaces ()
 			_input_bundle->add_channel (
 				surface->port().input_port().name(),
 				ARDOUR::DataType::MIDI,
-				_session->engine().make_port_name_non_relative (surface->port().input_port().name())
+				make_port_name_non_relative (surface->port().input_port().name())
 				);
 
 			_output_bundle->add_channel (
 				surface->port().output_port().name(),
 				ARDOUR::DataType::MIDI,
-				_session->engine().make_port_name_non_relative (surface->port().output_port().name())
+				make_port_name_non_relative (surface->port().output_port().name())
 				);
 		}