fixed!! Thanks to everyone for your help and suggestions.
Turns out it was the rotor arm in the distributor. And the choke sticking wasn't helping. (That was the non starting) The manifold is warming up evenly so doesn't appear to be icing either, but now have a new air filter on with warm air hose which should be better anyway. Carb's fine too, and so far so good!
thanks to Rob from Retro Auto in Dawley for sorting it, a good garage.