I purposely did not touch the engine as it was running like a champ before I did the tidy up!! only change has been plugs and fuel ?
I was bad and took it for one more quick ride- just to see if it was a 1st gear thing?
I was able to quickly shift to 2nd and 3rd then roll the throttle off and - yep she dies. won't start after that, as before.
I didn't want to start fiddling with stuff as it ran fine before 'refresh' but looks like I have no choice and its good to reset everthing back to factory specs (while keeping track of what current setting are too).
I may just thow the old plugs back in before I go stripping carbs- easy stuff 1st right
then onto your sugestions Andy