hi guys! bit of an odd question coming up!

So, i've got a 95 D1 300tdi and it's locks and ignition are getting tired.. ie, sometimes they refuse to work also, the keys seem to have been cut from some sort of house key or something.. not a normal D1 key.

my question is:

is it possible to change only the Barrels as opposed to the whole ignition and locks?

also, my mate's got a few Defender barrels he's selling and was wondering if they'll fit my D1?

looking forward to your replies

Edit: I've done the lock springs so it's not them