Finally I got it running today. Friday still nothing. I changed the distributor, but it turned out the burned plastic smell came from my starter solenoid that was soaking hot. I used a blow torch to clean the cylinders and plugs and checked I had spark with my glass spark plug.That was all fine, timing was set but still nothing. Checking the spark plugs revealed they were quite dry, so I had to recheck the carb. It just didn't give enough fuel vapour.
Today I reset the CO screw, installed a lighter piston spring (I had installed a stronger one) and refilled the damper with oil. I had also standby an eau de toilette bottle that I had filled with petrol, so I could spray petrol in the inlet. But it wasn't necessary, it almost fired immediately. Wow what a relief.
A bit later the heater hose sprung loose from the head, so that take off pipe has to be modified and the radiator hose comes dangerously close to the pulley. I have to make a bracket of some sort for that. But for the rest it runs sweet. I've videood all starting attempts so will be uploading a video later.
Now I have to sort a few electrical gremlins (when I push the horn, the left indicator comes on!), put the bumper and bonnet on and test it on the road.