You'd probably get a decent conditon standard 998 for that much, they do come up every now and then. I paid just over 2k for mine and when I first had it, it was bordering on mint. It's not so good now and I do try to look after it the best I can. So just have a good look around and look at a load.
I've already started having a look around but a lot of them seem to be unfinished projects which as much as I wouldn't mind buying my Dad would probably have a heart attack if he saw me buying one! How long ago did you buy yours?
You cannot guarantee the quality of a restoration though, it would be better buying a genuine car that is solid and only requires minor fettling which you could get for under 3k
Where would I get one though? 
Depends what you mean by well restored. You're looking at £2k upwards now for a very good Mini, anything under and there's probably issues with it unless you're very lucky.
£3k should get you a very well looked after example but you will have to inspect it all over to make sure, and make sure there is plenty of history as well. Buying off an enthusiast always helps (check the classifieds on here) as there are plenty of charlatans around. I have seen a lot of crusty ones with aftermarket shiny bits bolted on up for just shy of £4k recently, and they are having a laugh.
£14,000 seems an awful lot as surely even the last ones ever built didn't fetch that much when they were new!
I mean one that I won't have to start pulling apart finding tonnes of rust, I need to be able to drive it when I get it for it to be acceptable and for wuite a while without any major issues. I need to find someone who knows a mini inside and out ( I wish I could say I do but I'm not that good
) I don't want to get conned, obviously nobody does but it's taken literally years to get my stubborn Dad to even consider the idea and that would just reinforce the ''there aren't any good minis, they're all a pile of rubbish'' he seems to have going on in his head.
I have no idea why it was that much but I nearly choked and cried when I saw it, absolute beauty and REALLY well done job and they showed you the history of the job as well but I can't afford that