My van came with a very used alko hitchlock and one non-alko key.
The key works but having just one is not a good idea.
Toddled off to Timpsons but despite 3 attempts they were unable to cut a key that would fit and work - their blanks are too thick.
Wandered down the road to independent shop that was closed when we first arrived in town.
Key cut - no problem.
The "key" to this is the blank - Mine is a JMA ABU-51D https://jma-uk.co.uk/abu-51d-jma-abus-ab...inder-key-blank which is just the right thickness.
may not be of any help but who knows - oh and by the way , always take your hitch lock along to try it out