Thanks Benny,
The fuel tank pick up has been moved but to an ideal position and also I had half a tank of fuel.
The thinking at this stage is that given the carbs are on an angle which is not ideal every time I go around a left hand corner it is washing fuel over the air jets and effectively flooding the engine.
A lower float level may help but could also create bigger issues.
My Guru is suggesting making an aluminium block to go over the air jets with longer tubes inside them- he was saying this was used some years ago as the problem is reasonably common.
I'll try investigating this theory further but is does make sense and the car definitely does not feel as if it is starving for fuel.
Cheers
Dave