I won't go into the long winded story as to how what why and whatever.

Quite simply, I sold a car in p/ex to one of my biggest
customers nearly
2 years ago.The car was very troublesome before it went to them, but I finally after 4 weeks, got it fixed under warranty at the main stealer and completed the deal.
The car sat on the forecourt for nearly 12 months, but they finally got someone interested in it this January (09)
Within 200yds on the test drive, the car started playing up again...badly and worse than ever. It's now in 'limp mode', and their mechanics cannot after 10 weary months, get to the bottom of the problem.
The main stealer will only look at it for a cost, which he's not willing to pay.
The boss has been really sarcy with me over the last few months, going on about 'that heap of shit you gave us' etc etc.
Yesterday, I had to go in and do a job for them. whilst there, I asked the boss's sister for a c/q that is owing to me. She said, oh, sorry, he's refused to sign it, and wants a word with you.
I sauntered over, and he initially looked puzzled. "a word"?

Oh yes, that bloody car. I'm losing thousands on it now. I need to get it mot'd and thrown into the auction asap, but I ca't do that until it's fixed and running properly, so I want
YOU (me) to go back to the main dealer and threaten them with legal action if they don't fix what they are supposed to have already done, just 100 mile ago...(albeit bearly 2 years ago!)
I went to see them (another customer of mine) and yes, they will look at it and try and fix it, but cannot predict how much it's going to cost...could be thousands, we really don't know.
ECU? Turbo again? Who knows, but it'll be a min. of ?100 just to check it out.
No warranty as the car is now nearly 5 years old, and their remedial work is NOT guarenteed for 2 years.
What do I do?
Tell the selling garage (my customer that I don't want to lose) to get stuffed, as it's NOT legally my car?
I'll then lose him as a long standing customer, OR do I bite the bullet and pay for the repairs, whch could (and probably will) literally run into hundreds or possibly even thousands!

Basically, I'm backed into a 'moral issue corner', and I don't know what to do for the best.
