Hi Pilky
I'm a fellow Oldhamer and have had just the same problem as you describe with my Glee. It dated back to a tour of Germany in very hot weather a couple of years ago. It recurred every so often, usually after a long run. Thought for a long time that the problem was somewhere up on the handlebars...sticky throttle tube, cable problem etc. Lots of fiddling around but the fault would come back, usually when the bike and/or weather was hot. I had the 14,000 mile service recently and, while the tank was off, asked the dealer to look at any possible pinch point at the other end of the throttle mechanism. The linkages under the tank were lubed and I have just done 2,000 miles through Europe with not a hint of the problem returning.