-95 Disco, sometimes no spark at start-up

[1784]

This is where it started: http://www.discoweb.org/forums/showthread.php?t=44455
Thought it could be worth starting a new thread since it's a different problem now.
Well have the Disco had been behaving well a few days now, running OK and it's new exhaust making making muffled sounds for a change.

Then when I got out today to just move it out of the way, it just cranked, no start. Checked and there were no spark coming from the coil. No fuel smell.
Measured voltages and pick-up resistance which checked out OK and put back. Tried again and it started like nothing had happened. Ran OK and restarted OK.
What could cause the spark to dissapear? Low battery voltage? I had around 11.8 when checking at coil with ign on. Or is it the baseplate and pick-up time to be replaced now?
Coil and ign amp are new.

Thanks!

 

[I HATE PONIES]

Could you be having an alarm issue?

 

[1784]

I don't think I have a LR alarm (no spider issue) in this Disco, had a 96 before which had the keyfob etc, but this one just have the keys.
However there are remains of an aftermarket alarmsystem in it, but I don't use it. Tried to disconnect the main alarm unit but then it would not crank at all...
However, I think that if it was an alarm issue, there should not be 12V at both sides of the coil?

I don't think battery voltage should be the problem either, starter spins just fine and normally it's there you notice a bad battery on Rovers.

Checked airgap just now and I could just fit a .30 feeler, so that should be OK as well.