Immobiliser problem

Recently got stranded due to key remote failing to operate the central locking/immobiliser on my R19 (8 valve) RSI cabby (1995 model). Got car towed back home but now unable to use due to the above problem. Have changed batteries in remote - red light illuminates on the remote for about 1 second when button is pressed (also did this with older batteries too).

Any information would be helpful - can immobiliser be disconnected or are there other engine management issue to be aware of.

thanks