An Update:
A chat the other day reveals that the carby was cleaned, the slider, as mentioned previously was changed, and now we can add in that the valve clearances were also modified. (What to I am not sure, but openned up a bit)
I'm sure that this will slake the curiousity of some and arouse more interesting theories from others, all of which again proves the usefulness of the site as we all diagnose from a distance, and somewhere among the ideas the correct one is always the last one we try.
Again, Thanks for the help on this one. He's happily riding into the fading fabulous summer weather we are enjoying. A slight tinge of conflicted envy runs through my veins as i think about the now evaporated posibility of picking up a cheap super rocket. He aint thinking of parting with it now.