My drivers door lock is temperamental to say the least with central locking you have to push the fob button at least 3 times before it opens being the last to unlock so thought I'd try and get a 2nd hand central locking lock but not sure how easy to remove and fit that would be?

Also can I just unlock/lock the drivers door with the key or would that not disable the alarm?

See the link about lubricating/replacing.

http://www.landyzone.co.uk/lz/f9/central-locking-76573.html

You can use the key to unlock the door - when the door button pops up then press unlock on the fob ...or... as long as your transponder is working the rest of the doors unlock when the ign key is turned...I just tried this on my 98...alarm dint go off.

This is from the Handbook

Use the key to lock ...turn once for locked/alarm and twice (within a second) for superlocking.

(The way I lock mine all the time due to my volumetric sensor being u/s causing the alarm to go off 5 mins after locking with the fob).