Central locking is up and running now
I wanted to keep the external key barrels as a backup in case of electrical faults- it seems sensible especially on a 1980s landy, and I think all production cars with keyless entry retain some form of emergency key.
The front doors were easy enough to do as the kit includes fittings to connect the rod from the motor to the rod from the internal lock tab. That's basically all a universal kit does- a motor connects somewhere to the existing locking mechanism in each door.
I managed to connect it to the alarm system so now all three doors lock/unlock with the alarm remote. Using the key on either front door will also trigger the other doors.