Well I've got hold of some old CC magazines and found that the "Super B" did compete in 1994 driven by Bob Owen, and came 6th in the Pro Rover class with a best time of 11.65 in the Summernationals at Santa Pod. There were 14 Pro Rovers that year.
It then seems to have undergone a rebuild and didn't appear in 1995. It must have raced in one round in 1996 as the final points show "Oliver Owen MGB 50 points" 4th in class (only Paula Atkin 1600, Mike Szeley 1200, and Murray Kinnaird 400 points in that year)
On further checking the points are confused as there is no mention of Oliver Qwen or the MGB GT in any race report and three racers - Steve Green, Ian Hampstead and Martyn Moore are in the final round race report but not in the points table??? (Ref Custom Car Nov 1996).
So are there any pictures of it in 1996? and does it still exist?