Is it a "real" Ignitor 1 (which seem quite reliable - I had one for years), or is it a cheapo Chinese copy? Whatever, I'd deal with that open manifold connection first.
Are you 100% sure that when the timing marks are lined up, no.1 is at TDC on the firing stroke AND the rotor arm is pointing at the lead that you've got going to no.1? Sorry if I'm teaching my granny to suck eggs. (BTW as Snotty says, you've got to at least cap off that tube sticking out of the inlet manifold.)
I’ve sorted the tube, I just put the parts back in the engine. I’m 99% sure it’s pointing at no.1 TDC. I can send a photo tomorrow.. had enough today
So. It fires sometimes but won’t run! you’ve changed lots of electrical bits! you have changed carbs you have fuel it’s timed correctly you have spark you have replaced vacuum pipe. I don’t know how to check an electronic ignition works correctly but I’d ask. I’m guessing your tappets are set correctly and you’ve checked compression?
I’m thinking about replacing the Distributor just in case. I might buy a £50 points one and if it turns out to be a distributor I’m playing with the idea of getting a 123 and using the £50 as a back up under the seat.
If you are getting a spark it is almost certainly not the distributor or the electronic module. It should be a spark with a bright core with a reasonable "crack" sound to it, not a dim blue thing.. So now having replaced lots of parts, if you have a spark..repeat basic tests methodically.. Compression test. Timing.. Spark plug leads order check. Cranking fast enough (this sort of checks battery/ starter / earth straps) Post a video of it cranking, should be a regular pulsing sound to the crank, if its irregularly speeding up it could be barely firing, if its pulsing in a 1, 2, 3, 4 pattern that misses a beat you have a problem with one cylinder. And if you can also disconnect a spark plug lead and crank the engine and take a video of the spark and post that (e.g. Youtube then post a link here)
Sorry…didn’t read the whole thread. Where are you getting spark from, all 4 plugs, removed one at a time from the engine?