Disco 2 central locking problem (have searched)

Hi,
Disco 2 td5 2000, Central locking won't lock with remote... All doors shut, press key fob and nothing apart from a single blast from the horn, press door lock switch on dash and all doors lock, lock drivers door with the key, unlock works as it should apart from drivers door as needs a new actuator so unlock this with the key but not a problem (been like this for a while with no problems)

So the only problem is the key fob won't lock the doors and there is a single blast from the horn ???

Have done a search but not found what I'm looking for.... Any ideas.

Thanks

The driver's door latch assy must be changed cos the CDL switch in it might be fubar'd as well that could be the cause of the misslock and it's not productive to chase a wiring issue on that circuit as long as the actuator is not ruled out.

Thanks sierrafery,

Been wanting to change the drivers lock for a while but while it was useable it's gone down the list of jobs to do, will move it to the top now.....

Thanks