I got a Citroen Berlingo last year. Now 5 years old, 43k miles, cost a little under £4k. Drives beautifully, fairly quiet, 1.8l diesel is fairly powerful and very economical. And there's *tons* of room inside - enough for me, other guitarist, full PA rig and all our kit without even going above window level, or five people in total comfort. The rear seats have a clever folding system which is very quick and easy, unlike most estates, and gives a large flat floor. It's also well-designed for stowage spaces and stuff like that. It doesn't corner brilliantly, but then it's a van with seats in it so you don't expect it to handle like a sportscar - in a straight line it goes and stops quite happily. They were (and are) very popular, so there are quite a few come up second-hand. No reason you can't get a very nice example for £4-5k, or a reasonable older one for £3-4k.
As for reliability - well, the mechanic who's been doing our cars for the last couple of years has one himself. Nuff said really. :-) My only complaint is that the front seats don't fit my back, but a cushion for lumbar support fixes that problem.
Incidentally, I suspect that with a Berlingo you're really not going to need that trailer. The damn thing's like the Tardis - you can just keep throwing gear in there and it hardly makes a dent in the space.
You might have guessed by now that I *really* like this car. :-) It's the only one we've owned that I'd recommend to anyone without hesitation, and if this one ever got written off then I'd buy another one immediately.
Of course, if I didn't need to carry a PA system and everything else around then I'd be buying a Marlin/Javelin Cabrio, which is quite simply the most beautiful car I've ever seen. A close second would be the Autotune Aristocat which is a slightly widened XK120 replica. One of these days...