Thanks for that

I asked someone who fits car alarms for living.
The wire I have to snip is the Red with Yellow stripe. (Fuel Pump)
Says if I unclip the fuse box, to look for the Red/Yellow cable that runs
from the back of the box and then it runs back under the carpet.
He reckons it's the best option rather than go for the starter wire,
as the car can be bump started to get a car away.
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After spending a few hours looking for that Red/Yellow cable, (And not finding it) my head kicked in to thinking mode. The fuel in my car isn't controlled through electronics, (It's mechanical, not a fuel injection) Dooooh!!
I'll have to take the starter or ignition method of imobilization. And sort out something else to stop it being bump started (Dead lock of some sort)
Cheers