A leisurely afternoon's tinkering has taken me a little closer to the end game.
I managed to get the drive chain aligned but it still 'jumps' on the engine sprocket.
I'm ignoring that problem for now.
I changed the handlebars:
After my little victory with the throttle I crashed back to earth with a bump.
Whilst fitting it on to the handlebars I over-tightened it and the crappy black-plastic housing cracked.
It still works, so long as it's not used with vigour, but I decided to replace it.
A quick eBay search and the desired item is on it's way.
Having completed the purchase, I did a little more 'window-shopping' and noticed there's a company in Bognor that supplied the same item and it's only up the road a mile.
All that's left to sort out, to make the engine run, is a H.T. lead.
All that's left to sort out, to make the engine stop, is a kill-switch.
Just don't ask about the 'Kill-Switch' debate, really, don't.