We've settled on a 406 HDi estate. It's about 4 years old and slightly high mileage, but it drives really well, smooth, quiet and reasonably powerful. The first thing we tried (a 306 estate) didn't really have enough rear leg room and the engine didn't sound good, although it handled better.
We also drove half way across London to look at a used car supermarket (claim to have 5000 cars - believable). The only really suitable car was a Mundano in a foul purple colour. Didn't even bother to drive it, since it was no better than the 406, but £800 more expensive. Chris also saw a silver Volvo with cream leather interior that she thought 'looked comfy'. But it was petrol rather than diesel, and about £2500 more than the 406. Forget that one then.
It's funny. Each car we've had for the last few years has cost about the same. The BX estate cost £4700 and lasted 6 years/185,000 miles. The current 406 cost about £4400 and lasted 4.5 years/142,000 miles. The new one is £4995 and will hopefully last to the 200,000 mile point. By that time the kids should have set up their own homes and we can get something a little more exciting. Or not.
Anyway, the car should be ready in a week or so. It needs the front discs replacing (they're warped, and braking was way under par) and a ding fixed on the driver's door, plus a new battery. The paint is a bit 'flat' courtesy of too may drive through car washes, but other than that it seems good. Now we just have to pull some cash together.