Alright so update on this.
Pulled out the fuel injector. The bottom o ring on injector 1 was completely eaten away so swapped it over.
Changed ignitor modules to the matching number of my original and the rev limit at 6500rpm has been removed so back to being able to rev to 8000 - 9000rpm if I let it.
So the two things that caused all my problems were the ignitor module going bad which causes the car to fuel up massively. The second was a leaky injector from the rubber o ring wearing out. So that's all solved now.
The only issue now though is that the CAT temp light is still coming on after driving for maybe 1minute.
I assume the that maybe the CAT is clogged or ruined because of all the excess fuel? any ideas? I seem to get a few small pops from the exhaust when I lift off the gas if I rev it out. This didn't really happen before. Could it all be related to a blocked CAT or something else?