1978 Mini 998cc

Evening all.
Im having an absolute nightmare with our 78 mini. It all started on Christmas day when it decided to cut out 5 minutes down the road, we managed to get it back but it was spluttering and cut out a few times, we eventually had to tow it the last 1/2 mile.
Since then I have changed and set up the points and condenser and its had new spark plugs and leads. After fitting the points and condenser, it did improve and ran great for 30 seconds and then it just spluttered and died.
Ive been advised to change the ignition coil which I have, twice. First for a 12v ballast type and then for a 12v non ballast type as there was confusion about whether it is ballasted or not, even now I am still unsure about whether it is or not When I fit the new coil it actually got worse than when it was running with the old coil (dlb101)

Any ideas would be greatly appreciated.

Is the earth from the Engine to the body ok? I’ve had similar problems in the past, and its been down to the earth strap. I’ve also had odd ignition problems down to connections. (i’ve sanded the contacts on the fuse box in the dark before now to get things working!)
Finally to show how dozy I am. When I first had my mini I was riving along, it sputtered and died. because I’d put the tab onto the points the wrong way round on the clip and it shorted out to the distributor backplate intermittently.
Dan.

Sounds like it could be a fuelling issue.

Does the float chamber remain full (checking supply - fuel pump)?

Have you taken the carb apart to check for a blocked jet or muck in the carb?