Just to update, it does have a ballast resistor but I have even tried another ballast resistor and coil - nothing changes.

I have now removed the dizzy and checked, setting the timing to static, this was just a few
degrees out as it was originally set dynamically, yet to bolt it all up,
late in the day now - you don’t get these problems with a German car!

Thanks for everyone’s help


Mark

1979 4/4 crossflow twin 40’s