I'm currently running a small project to put together a "MOT-ECU". It will use the original ECU connector and a $2 timing circuit I got from Ebay, and a broken ECU will be a perfect donor for the connector.
A small youtube clip showing the MOT-ECU in action! :-)
The only thing this "ECU" does is to light the airbag light for 2-3s when you turn on the ignition. Just what you need to get through the MOT.
All components removed from the original circuit board to make room for the timer board, wich will fit nicely in the original box.
Outputs to squibs short circuit to avoid accidental triggering of airbags/pre tensioners.
The only connections used are +12V, ground and lamp.
Ebay link to timer board: