I could have sworn it was nearer two but I guess Renault would know
Just found this article though, which also puts it a lot nearer 2K less for the Tesco Value 172 as well:
http://www.autoexpress.co.uk/car-reviews/15219/renaultsport-clio-172-cup
That quotes 12995 for the Super Saver and 15095 for the normal 172, so 2100 different.
Edit:
Just checked on heritage and it quotes 12,995 for the price of a the 172, and it quotes that at the same time (from Nov onwards) the normal 172 was reduced to 14,595, so therefore only 1600 quid difference.
You seem to be quoting the Jan 2000 price of 15,995, but they werent for sale at that price at the time the cup was out.
So TBH I think my initial recollection of 2K is probably about the sensible average to quote really mate?