Thank you Ray for your detailed response.
The current key/lock set up is 1 key would have operated the 2 doors and the boot (if it wasn't for the mk2 lock replacing the original lock at some point, on the passenger door) The ignition lock is operated by a different key to the doors and boot, which I believe is standard, the ignition key is a larger key not dissimilar to the mk2 in style but a different cut i.e.. different profiles.
The car is a 1974 1.3l model and indeed the key is an FV type, so all good their.
I had understood that the key hole had been enlarged to accommodate the mk2 lock, due to the work involved I probably will not change the lock but wanted to purchase a standard mk1 door lock, if any time in the future it was a requirement.
Now you have advised that the locks are not handed, I will seek to purchase a single lock to keep with the car.
Thank you again for taking the time to help, very much appreciated.
Dave B