To the OP, just to throw a spanner in the works, here's my suggestion:
Sell your mini, get £8k for it. Now, put £5000 in the bank, congratulate yourself on no longer being in debt for your car. Then, go out and buy a Japanese, petrol engined hatchback for less than £3k.
I've done it before (and I'll no doubt do it again) but I'm going to pimp my Civic again. It's a 1999, T plate 1.4 5 door hatch. It's not fast. It is very comfortable, and has a good ride quality. It does between 35 and 40mpg, depending on whether I'm on the motorways up and down the country on the way to and from gigs, or hooning around the roundabouts in Milton Keynes for work. It's been reliable so far. I bought it, and had the cambelt changed - it was due on the schedule, and I do it on all my new cars anyway. Since then, I've changed the oil and filter myself (with oil I got free with a magazine subscription and a £8 filter), changed the brake pads myself (cost ~£30), and replaced a torn auxilliary belt (cost £4). In this time, I've done over 26,000 miles - and I've not had to spend another penny on it.
Just spending £10,000 on a car doesn't automatically mean it's going to be reliable and trouble free.
(touches wood)