You should easily get a really clean one and insure it for that money mate, theres quite a few out there so dont rush into anything, you should be looking at stage 3 with 60k+ or mildly tuned with a few less miles on, really low miles and you are looking at 16k+.
Thats just my opinion though so its just a rough guideline.

Dont go anywhere near this though whatever you do. http://cgi.ebay.co.uk/ESCORT-COSWORT...item27ac9ce1b3