Hmm You be lucky to find an ECU... they dont make them anymore...
I hope you find the problem... my b/f just had to scrap his 414si after a new ECU, full service, new tension leads, dizzy cap etc... the darn thing still wouldnt run right, and each time the garage (2 tried) could not find anything causing it to run rich.
It would not pass an MOT so is unroadworthy. :-(