Breadvan ignition barrel issue

Hi all. Hope you are well.

Having an issue on stock 1983, 1043cc breadvan ignition. Key is struggling to catch in the ignition barrel. Pretty sure it's just because it's an old key and it's worn down. Are replacement barrels hard to get hold of? Can i use a barrel from a different car? Having same issues with door and boot locks. Again, pretty sure it's the worn down profile of the old key. Can replace door and boot handles easy enough, just need to get ignition sorted. 

Any advice is always gratefully recieved. Thanks for stopping by and any xp you can drop.