Hiya Icarus - not spoken to you for years . It's a real blast from the past seeing that old ABS diagnostic text I put together; - I must have written that nearly seven years ago lol. Still got your RS2000?

In terms of this ABS fault - a lot of the key ABS wiring goes through the main fuse box which has presumably been pulled about considerably when the alarm has been fitted. This could potentially have affected one of the power feeds which could cause either the instant or delayed light symptoms above.

Simple things first and all that - check the two ABS fuses (can't remember which ones they are now), and the two relays. Whilst you've got the fuse box dropped down check all the plugs are fully pushed in as they sometimes come out when the box is dropped down.

Years back when I had the ABS problem the light would go out and then come on again when you moved off. I was convinced it was a dodgy sensor - but they seemed ok. Ultimately it turned out to be a burnt out track in the fuse box which I fixed with a 10p piece of wire. Soddin Ford and their cheapo fuse boxes