I checked for a spark, set the timing roughly, fitted a new set of plugs and went for it - nothing[V] Checked for a spark again and nothing - a quick check revealed the +ve feed had come off the dizzy. Tried again and........vroom first time start[8D] I started it without connecting the cables to the carb and once I knew all was OK went to sort them out. The ends were a bit frayed and no end of poking and trimming would make the accelerator cable fit in the little clamp, further inspection showed it had started to unravel all over the place[V] Where to get a replacement on Easter Sunday? Halfords is open

A quick trip to the bike section and £3.50 lighter for a universal brake cable I set to work. I had already shortened the original to fit the SU so there wasn't any point in buying a proper one just to cut it up. I selected the best end of the cabe to fit into the bell crank and snipped the other end off, it cut nice snd clean with no frayed wires sticking out. The adjusters were salvaged off the original cable and after cutting the new outer cable to length everything was assembled, threaded through the clamp on the carb and the excess inner cable cut off. The accelerator now works perfectly, lovely and smooth with full travel - before I could only get about 3/4 travel so the cable must have been on it's way for some time.
After a bit of coarse- fine tuning with dizzy twisting and idle adjust the engine settled into a nice tick-over, a little lumpy but lots better than before. I ran it up to temperature and the fan cut in and out as it should - a couple of jubillee clips need nipping up but appart from that it's water, oil and petrol tight[^] It still sounds a bit rattly at the top end, my fault I guess for fitting a slightly worn rocker shaft - I got the best pair I could from what I had available but a new pair will be fitted as and when I get fed up of the tappety tap.
I couldn't set the timing properly as my timing light is beyond reach, blocked in by Harvey, and I cant move him because I've got no gear linkage fitted yet but it will all be sorted and tuned next weekend
Two's company