Thanks for the advice guys!

Will look more closely at the Tom Tom Rider and Garmin Zumo, but I think I will need one that accepts a remote GPS antenna, as my M3W has the updated gear lever, and the sat nav will be hidden well under the dash.

In fact, I doubt I will get to see the screen very easily, as the steering wheel and gear stick will obstruct it. Will be more reliant on verbal instructions through the intercom or swmbo. Will make a change from SLOW DOWN! Who at Morgan was responsible for putting the speedo directly in front of the passenger doh