Well for 1500 i'd look at a very nice mk5 zetec s, you can probably get one with a puma lump for that wedge, just make sure its solid and not rusty (rear arches are really prone!), unless your after really good mpg figues which in that case I'd avoid.

For £2k I'd be looking at mk6s but its probably base models rather than a high spec tdci, although if you hunt I'm sure you could find something

£2.5k gets you mk6s with 1.6tdci's is the sort of car you're looking at.

Hope that's some sort of help