Connect immobiliser to central locking

Hi Just bought a Defender 90 hardtop 61 plate.

It has what I assume.is a factory immobiliser / alarm but not central locking.

I have installed a central locking aftermarket kit and it has the ability to wire into outputs from alarm systems for lock and unlock signals - just simple switched negatives.

Does anyone know if the immobiliser ecu has a lock and unlock pin that can be accessed? If so where would the harness be located with the empty pins?

Thanks in advance