Hi guys and I should have realised the choke setting was on (not just in the borrowed internet pic, but on my real life carb), and hence the gap.
Huge thanks, and I'll do all of the above
Edit update: Adjusting the screw did the trick
And on...
.. Yes, a human issue here, but with the previous owner - I didn't want to confuse things, but the main "binding" problem is in the misalignment of the accelerator pedal, as the cable comes into the cabin through the firewall then turns 30 degrees downwards to meet it. Thus, despite oiling/ greasing the cable, it's still slightly binding (and will eventually fray).
The query above was designed to 1) achieve a temporary fix while I get the pedal re-aligned (not as easy as it sounds - don't ask) and 2) establish how to get the tickover achieved through the carb, rather than the cable, in any event, for which many thanks.
BTW, despite the 30 degree bend, the cable is not frayed, and it drives perfectly safely but - again - does need fixing, and the cable replacing. This is now scheduled.