None of the above, but I am treating the alarm as a suspect, because it, well, sounds a bit sick on battery backup.
Cheers for the offer mate, I'll do a bit more scrounging tomorrow and see what I come up with and yeah I'll flick you a PM, I live out of Gawler. Its been happening since the engine conversion, it seems like its getting worse, but it might be my imagination as uni has finished so Im looking at the car alot more.
I'll try that tomorrow and let you know what it says. pretty sure it was reading 13.6-8 volts on idle at the terminals, and it would drop about 0.3V when you put the lights on. I will confirm tomorrow and also check what its doing at 2000rpm.
Thanks guys!
Just reflecting, the car sat for months and months with no engine, if the battery backup for the alarm kicked the bucket from being dead flat for so long, could that zap voltage?