Hi Danny.
Swapping from carbs to EFI seems a bit "sledgehammer to crack a nut" solution to me. The car was designed to run on Stromberg CD 150's and there are plenty of people still running their GT6 or Vitesse on them, with very few persistent running issues. If it was me, I would stick with the carbs and plod on, trying to eliminate one component at a time, rather than swap lots of things at the same time,as it muddies the water.