Just seen this post. GS motorcycle tyres come to you and seem fairly reasonable. Ford & Ellis in Chesham can always help. Got a new mechanic familiar with BMW. I'm in your neck of the woods but don't know MotoScot, got any details.
got sorted by Colin who is, indeed, a top man and did a very professional job and no messin'.
Motoscot is Steve Grover who is actually near Luton but is a time-served BuMW mechanic who knows every inch of the bikes. His website says it all: www.motoscot.co.uk
His workshop is in his back yard and is immaculate. You can tell the man by the way he works, which is careful, thorough and tidy.