Mazda 323 alarm help.
 

I own a '93 323f and have recently had an issue with it.
It started fine one morning and off we went for the day.
In the afternoon I tried starting it and it just turns over but won't start.

The AA came out and said there is fuel, the distributor is fine and their is plenty of air.
Looks like the ignition coil.

I changed the ignition coil and it is still only turning over but not starting.

A friend suggested it may be the immobiliser has kicked in and won't shut off.

Does anyone know how I can reset or disable it??

A reset would be preferable as I obviously don't want my car vulnerable without an immobiliser.

Any advice at all????????