Does anyone else remember the locks/keys used in the 70's?
As I recall, the same lock was used by every manufacturer, and there were only ( I think) 99 different keys
Caravan retailers used to keep a peg board with copies of every key, no ID was needed, you simply had to ask for 'a number 34', or 'a number 9', or whatever you required.
Armed with all the keys it would have been possible to enter just about every caravan in the UK! - freinds who managed a dealership that closed down gave me (among other caravan items) a box containg about 70 of these keys - which, I hasten to add, were not used for any nefarious purpose
As has already been stated, though, caravan locks are more of a serving suggestion than anything else - any self respecting 8 year old could force such a lock in a minute or two. When we owned MH's it always seemed faintly ridiculous to me that so much emphasis was placed on can door security (tips about chaining the door handles together, that sort of thing) when many MH's had 'garage' doors, and similar access points, that relied on the usual cheap plastic caravan door lock