Totally confused now

Hi,
106 Zest 2 2001 diesel
I've been having crap loads of trouble with the electrical system on this otherwise ace car.
Started back last December, the starter fired in whilst driving, resulting in new starter, glowplug relay and ignition switch.
When it does this it throws in the starter just on ignition hence the ignition switch.
About a month ago if burnt out all 4 glowplugs in one hit,
Two weeks ago the starter fired in again, screwed the starter so yet again replaced starter and relay. There was still power getting to the activation wire so got a new ignition switch and tested it on a multi meter to make sure that there's only power to the starter wire when in the start position. All was well until I put it on the car. The wires were plugged in in exactly the same position as before (which obviously worked for 6 months) but yet again the starter fires on ignition only.
The battery is going flat overnight, and the reason I think it's doing that, is the 204107 relay is clicking in and out with the ignition off (yep replaced that expensive relay as well) I've unwrapped the loom following the activation wire all the way back to the switch and I can see nothing connected to that wire, it goes over to the big round loom connection plug where it turns to white and then continues to the ignition switch where it goes back to the blue on the switch.
I don't know why it's getting power just on ignition, and I don't know why the relay's clicking when the ignition's off.
The only thing I can think of and it's an easy answer but un-provable is the ECU.
Any ideas please?
Derek

 

Its a long time since I played with these.
Have a look down in the n/side of the engine bay. You will find a big egg shaped multi plug. Turn the release bit and pull it apart. I`ve known these to get red hot and burn. I think there is another one under the radiator?

 

Cheers Old Pug,
Yeah been through that and found nothing untoward.
So I've put in a separate starter button on the dash going direct from the battery through a new fuse box, and a wifi remote disconnect on the battery so it's off overnight and wired the radio direct to new fuse box which is live at all times
There's been no change regarding dash lights and now I know it can't fire when it wants.