Be very, very wary of anything that used to be a taxi. Maintenance is often skimped on and the long hours and galactic mileage really take their toll on the components, especially lots of stop-start in-town stuff

 

That sort of budget should get you into a 2005 Ford Galaxy, SEAT Alhambra or Volkswagen Sharan. They're all the same car basically, only the badges are different, and they're all solidly built, but check for lumpy idling on the 1.9 diesel and make sure it delivers power smoothly. Buy something with as much service history as you can and be choosy - there are lots out there.