Thanks you all. I will re-check float level and integrity.
I remember BP98 mentioned here a couple of years ago but I had the understanding that the BP98 was the one to use.
I've been chasing this problem around for ages. Rebuilt the carbie a couple of times over the past few years and still getting it run rich on RHS bank with fouling of plugs after each drive.
One think I never did was swap out the fuel tank which I knew had rust in it from previous owner. I just put an inline filter on. I now realise there is probably very fine rust coming through. I have a new tank I brought back from the US about 6 years ago and never put in. So I'm going to do that, along with new fuel lines, clean pump etc. Then re-strip carbie adjust, etc and go from there.
In that video I was revving to at least 40-50%. It may not be under load but it looked like a lot of fuel to me. More importantly, it looked like more fuel on the RHS nozzle than on the LHS. Which could affect the RHS bank even with a single plane intake manifold.