I have had a local auto-electrician round this evening - he's a fine fellow with an interest in classic cars.
Well, he sorted it - basically the points needed cleaning/adjusting (and I thought I had done that!) followed by towing the car which got it running.
It will start just fine now but I need to go through it now tidying up little "bodges" that were done to try and get it running. Then a few confidence building miles will follow.
But - what a relief!