Yes, I single stepped some of the code and found it some ORs and ANDs on a couple of hardware addresses, that sounds like an idea.
I will try and have a look tonight, I may not have time (playing football then quickly back for Enterprise on Sky). Am I right in saying it is a GAL? some kind of programable chip thing?
If not could I not simply replace the clock on the Catt, okay this will dissable the on/off functions?