That was probably me trying to demonstrate the performance to a caterham owner though there was a bit to much traffic . Sorry did not notice you in the van but did have a bedford mini van race me away from the lights later on ! David
Must say it didnt look like you David! only see you briefly on the nearside as you pulled up onto the bypass. (and I suppose its dark in there too )then you hung back for a while until opening her up see you go off at next junction and then back down westbound again.
I was the white van man giving it some "wind it up " out of the window 
Sounded nice 
see you go off at next junction and then back down westbound again.