Hmm, a lockset change is an issue in itself (and expensive). If it's just the barrel, you might be able to get a locksmith to change the wards from yours to another barrel. I'll have a look in the garage - I know I had a spare driver's door handle with barrel but I might have thrown it out when I moved from s P38 to the L322.
You could also try Triumph Rover Spares in Adelaide. They claim to be the world's largest LR dismantler. When I tried them a few months back, they didn't even bother replying to my message via their Contact page. It might be better to ring them. Triumph Rover Spares - The World's Largest Land Rover Dismantler

