Hi Alex,
Thanks for the info. I've been told that it should work with any Mk1a ECU but then sometimes you read that that may not be the case. Unfortunately someone else in the club needed a 1a ECU so I gave the ECU away almost straight away. Anyway, the bidding started at 99p so we'll just have to see where it ends up. I'm not under any illusion that it's worth mega money. However, I've built a MegaSquirt since then, (not for a 4AGE) so don't feel I need this lying around anymore. I'm not sure it'd need 5-6 hours to map this if it's on a relatively standard or lightly modded 4AGE. If the engine is more highly modded, then personally I wouldn't be sticking a piggyback unit on it anyway.
Saying all that, I am probably writing up a for sale post for everything sometime this week...