I've finally done it!

Brown is now running like a dream. I balanced the carbs, topped up the dashpots with ATF and I set the points and she is running perfectly. No backfiring and no hesitating on hills. I'm so pleased. I also managed to quieten the exhaust by nipping up some of the joints. There's one joint which will need a new clamp but that will have to wait until my next pay day.