- I live in Belgium, so there's no point of me going to the UK to have my bike serviced there, although I may reconsider, the £ being where it is now...

- If I travel to a country where I don't speak the language, I always try to eliminate forseeable avoidable discussions. Seems reasonable; adventure to me lies in having fun. This leaves the unforseeable hassles that will pop up anyway, on any trip. I've had my R12GS's breaking down in the UK, France, Germany, Spain. Although I speak these languages fluently, I don't master all technical terms, and knew I was at a disadvantage when communicating.
- I've been to Lisbon, and agree that it's worth visiting while a bike's being serviced. But perhaps that wasn't the OP's idea. Your tips may be helpful though.