ahh. A VAG fan.
Audi 80/90/100/coupes are FAR older designs than a mk2 mondeo. First A4 was what, hmm, M/N plate? Mark 2 mondeos were a 96 P. A quick autotrader search shows 2 sub £1k passats around here, 1 a 93 and 1 a 94 reg. For a mondeo you're looking at 96/97 cars really for that much (one or two 98s too).
Build quality etc on a ford mondeo now (mk3) is as good as a passat. Also the tdci130 ford engine is a far superior engine (chain driven and a wider power band) than the pd130 vag unit. Mondeo also handles better than the passat (the passat tends to float along with less feeling through the steering when on backroads, better on the motorway though). Unreliable? Ford are one of the least called out manufacturers according to the ADAC. Although old fords (sierras etc) had a tendancy to rust pretty badly that was pretty much sorted with the mk2 which is a good car.
Rover 600/vectras aren't too great cars though, the 620ti is probably the only 600 i'd consider and well, the vectras look good but its a shame they're not overall good (especially considering the cavalier wasn't a bad car).
Strauss- why are they 'awful, funny little cars'? Care to back that up with reasoning?
At this price bracket a mondeo really seems the best choice for AT82.
edit- not sure about the focus. Looking at the prices of focii versus those of mondeos (98/99/00/+) cars the focus is usually more expensive- e.g. £4k for a 2000 focus versus £4k for a 2001 mondeo.