Have you tried MR2 Ben in Deeside

(
[email protected]) he used to have quite a large stock of used ECU's.

Not the cheapest, but if your stuck he might be worth a try.

Have you opened up the ECU to check it's not the old leaking capacitor issue which is quite common on older ecu's.

Easy to spot by the gunk coming out of the bottom of them.

Assuming no major damage to ECU tracks, the capacitors can be replaced and minor repairs made to tracks if needed.

Paul