It appears 4 or 5 times in the series 10 episode with the Britcar 24 Hour race.
It’s at about 5:24 in this clip from the show (you can see the back view of it at that time).
http://www.streetfire.net/video/129-top-gear-britcar-endurance-part-1_187505.htm
Almost looks like a TVR, but I don’t think it is.
Good call! That’s totally it. 
Thanks so much dude!