Thanks for all the comments, I never bothered with a satnav on my previous bikes as they were all limited on cockpit space as they were all sports bikes, however I have now managed to win an eBay bid on a Tom Tom Rider V5. A bit of an older piece of kit, but with lifetime European maps, should be fit for purpose. Also got some connectors to wire it into the spare power connections behind the screen, so that it will turn on with the key.
Cheers
Denjy