Thanks all, things got progressively worse today. Originally the light would come on and a few minutes later be out. I narrowed that down to the light going off whenever the clutch was depressed and RPMs dropped off, but now the light is on all the time.
I've located the plugs and it looks like it's showing 3 faults....
22 - Knock Sensor
14 - Idle control system
33 - Vehicle Speed Sensor
So, code 33 would be expected. The other 2 I was not expecting. I know what the knock sensor is for, not sure if I should be worried or if that was triggered as a result of me testing as I took it to about 4k with the check light on and power was brutally cut?
I connected up the green plugs (along with black ones) to reset the codes, went for a drive with them connected and the process worked but at stage 8 of resetting the codes, the check light was signalling code 33 only, Came back disconnected the green plugs and read the fault codes again, all 3 fault codes still present. Edit: That said, the check engine light is off right now.
@savage bulldogs It was sold to me as a v3, I'm a scoob noob though, how can I tell for sure? The export cert shows first registration being Jan 97, Serial GF8-021069 with the EJ20 engine.