Just to confirm Ford Ka part 'Fuel rail hose connector elbow' part no 1072003 (98MF-9L276-BA) does perfectly replace the Guzzi/Aprilia/Piaggio part.
When the other parts arrive i will put in a 360 turn of pipe to give me more free play to undo the connector.
The only risk I can see is the fuel in the pipe expanding and giving less power per mililitre through sitting in the hot V of the engine - but as the tank is already in that hot zone I am not sure it will be a big problem.