I just thought I'd post this for the benefit of others as I know how difficult it can be to find a really good mechanic. On a recommendation from a friend I've just had a major service (including valve clearances, which on a F800 is a big job!) done by Mark Wright near Salisbury. Here's his FaceBook page:

https://www.facebook.com/WSandR

I tend to do the minor servicing myself and so I know a little about mechanics but I have to say this guy really does know his stuff. The work he's done on my bike is superb with a lot of attention to detail... He's a former Navy Engineer and Honda trained tech who's set up shop by himself.

I thoroughly recommend him!