Well, finally got the locks sorted. I went to a local caravan repairer and after perusal of his trade catalogue we ordered two keyed alike Vecam brand locks. These are almost identical to the locks used by Eriba, other than the colour of the inner metal barrel, silver rather than brass. I did have to change the locking bar over, the Eriba ones are bent at an angle, no problem as the the thread size is the same, took all of 5 minutes. Total cost £44.17!
Bit different to the £70 each wanted by AL!
Forgot to take a photo when fitting but here is the pack in case anyone else finds it useful.
D9C19F2C-5392-44B5-8106-03BF8C5D47DA.jpeg - Bild entfernt (keine Rechte)