Right, left it in to McNamara's for a few days, they did say that the lambda sensor was reacting slowly and they replaced that. They are not convinced however that it will be enough to pass. The levels still fluctuate around the pass/fail mark. I'm putting it in this Friday, with the usual additive tricks and keeping the exhaust hot. Fingers crossed.
The only good news out of the whole lot is that I do have a Tom's ECU. "That's some fancy ECU you have in that car," - quote. They said that the ECU board itself has been modified, but as such they can't do anything with it. The mixture the engine is receiving is deliberately a little on the rich side, to maximise performance. Not so good when it comes to emissions. They did say that if it failed again, I would need to consider getting a new ECU. I was wondering if members here had standard ECUs in their own cars? Are they interchageable? If it failed, would anyone consider swapping their ECU with mine for a day, while I put it through the test?
That said, I'm hoping it won't come to that!
Also, which would be better to have in the in the tank, Shell V Power or Maxol E5?