I had the ECU repaired on the Meriva a few years ago now by these people:
They also repaired the controller that went with daughters Connect fuel injection pump but when tested it failed (potentially down to the pump). They offered us a full refund but as no one could prove where the fault was I just took 50% (as they had been very helpful in the interim).
With some of these things I don't think it's just the straight cost of the repair versus the value of the car but the value of the use of the car, the likelihood of it just being that (or not) and how likely it would be to get something else that wasn't just someone else's leftover problems?
Cheers, T i m