Hey mate, I have an SR myself and had the same problems as you regarding the ECU. I assumed a simple swap and my car would be up and running but nope, nothing! so I ordered an ECU from Ed which bypasses the built in immobiliser. Problem is, ive bought another car and no longer require it so its up for grabs. I paid £150 for it a few days ago and it hasnt been used.
If you fancy giving me an offer then im willing to sell it as its no longer a requirement since the purchase of my 1994 Dot... non nats haha
Craig
Repair with a porcelain one off ebay - no more trouble....easy fix.