I posted a few weeks ago how my remote central locking (IR Type) suddenly stopped working, had a fiddle with it, tried new batteries in the fob checked fuses and had a gander at the wiring for the locking ECU but can't see anything wrong.
Because of this i'm having to use the key to open the door but it's very very stiff on the drivers side and it is now becoming a 10 minute procedure to open the car as once i put my key in the lock and open it I can then not turn the key back in order to take it out of the lock without a hell of a load of wiggling and relocking and then unlocking again. I now don't bother locking it any more as the hassle of getting the thing open is just too much of a pain.
The lock in the passenger side door seems to work fine so is it possible to transfer the barrel and other bits into the drivers door and if so how easy / fiddly of a job is it.
Had a similar problem just the other day.
This is the easier way to sort the lock, without having to remove or replace.

Remove the door card, and liberally spray all the lock, linkages, rods, and mechanisms with some Lithium grease.Then do it again for sure. Test, and replace door cards. Job done.
The reason I know this, is, my local garage stated, 'people continually use the remote fob to lock/unlock the car. The lock never gets used, and siezes up, making eventual entry with the key very difficult, as the whole lot is 'stuck' together'.
He said this is the first thing he would have tried if I left the car with him...
Believe me, it worked. 20 mins to remove the door card, and two long sprays from the grease can, left for 5 mins, SUCCESS!! Saved me a fortune.
Certainly worth trying before trying to swop lock barrels, which, looking at Mr Haynes publication, seems like a nightmare!!
Try this tip first. Might just save you a LOT of trouble..

Hope this helps,
Dodger.