Hi Slider, thanks for your reply. I have resolved it now. In the end it was` nt fuel at all or lack of it ! We had established that it had voltage as you say, and checked all the timing marks which all lined up, except when we took off the blank lid on the distributor (I have wasted spark ignition) and found the shaft to be about 20 degrees out ! The pinnion had turned on the rolpin. So I decided to put a new rolpin in and then put a smaller rolpin inside that one to beef it up as it seems to be a week point. I know the rolpin is a sort of safety valve to avoid damage to more serious bits, but I will take that chance. I now think it was loss of power that caused me to drift out and go off the track at Goodwood.
See last reply for youtube link.
I`m off to Crystal Palace next weekend for the two sprint meeting (Motorsport at The Palace) and have noticed my starter motor is sounding a bit like its on its way out so thinking about one of the powerlight starters to replace it.
Cheers