Stuttering investigations

After a post on the forum, speaking to Andy Bates and a hunt on the net, I took the car for a blast up a private road, and it showed no problems. It has to be fueling or electrical, but i'm not going to be able to test it properly until qualifying at Cadwell, so i need to investigate/repair as much as i can now. I have ordered a new set of plugs as a precaution which i will fit and have a spare fuel pump and set of coils which i will take with me to cadwell. I cleaned the fuel filters and removed the tank and cleaned it out, there were some small particles in there but nothing severe so doubt it was the cause.  Dave (the old owner of the car) suffered something similar when he owned the car. It only happened when the car was hot, but that problem turned out to be a vapour lock in the fuel line caused by the pump being in the engine bay, so he moved it to the rear, so it can't be that again, unless the pump is on the way out. I tested the flow rate of the pump which worked out to be about 2 litres per minute, so that seems fine. Derek has suggested it could be rubbish in the float bowls as he suffered a similiar problem back in his class C days, so i'll have to whip the carbs out and have a look.