That's good of them, how generous was the cash offer compared to the value of the car? I guess it's cheaper for them in the long run rather than court time & insurance etc etc.
I would say that their offer was almost exactly right for the car and mileage. Today I have bought another one which is 3 years younger, 30,000 less miles on the clock and with more stuff (e.g. electric windows and drivers air bag) and only had to part with £175 net.
No V8 - 1.3 auto with a 3 speed box