Is this the correct throttle lever mount for an 18" Atco Standard?...
Adrian
...and if not, does anyone have a correct one kicking around I could beg/buy/borrow/steal?
The lever itself is not - it's attached to a single-lever Villiers carb that is slightly too large for the stub, possibly off a later Atco Deluxe. A couple of members have kindly said they'll look through their bits collections to see if they have a correct carb (Atco or Senspray?), but there's currently no great hurry. 
Having had a brainwave …
Having had a brainwave (makes a nice change from a brainfart), I found the Atco Standard handbooks in the club files, and took a look at the parts diagrams.
As far as I can see, the Standard doesn't have a throttle lever mount, it presumably fits round the top bar of the handles. If so, this means I have a slightly short top bar. What are the odds on finding a spare the right length? Am I about to fill my shed with dead Standards? Or do I just leave the incorrect mount as part of it's history?
Bloody hell, I've only undone one nut, and already it's like the riddle of the Sphinx!