Thanks guys for your offers to help, I had a look at the ECUdata scan thing, I already have a Tactrix cable so was after a program to run on a computer more so than a stand alone bit of kit. But if I do run into CEL drama again I will ask.

Thanks for the pearl of wisdom nauli.
I did a few WOT 3rd gear logs and sent them to a tuner, he said safe as long as you dont go mad. But I went mad and got stung! What Im saying is theres a degree of educated risk assessment going on, as long as you stay in CL fueling its all good (in my situation). And its only until I get a tune done anyway. (that doesnt involve getting burnt 2.5K)