Hi chaps
Thanks for all your advice as usual,I have just road tested bike after gearing up on the engine sprocket.
It has made such a difference! It not just the fact that 55-60 cruising now feels very comfortable which is what i was looking for , but the fact that going through the gears you can "hang on to each gear for longer so forward progress seems so much better" All in all a worthwhile few hours in the garage .
Spyke