This find may be of interest or use to others?
My new-to-me boat came with no keys for the hitch lock,; although my insurance co requires a wheel clamp, I have in the past found hitch locks to be useful. My Lugger had only one key, and that always made me particularly nervous, in that the hitch could not be operated at all, unless the key was in place! ie no key no hitch, it could not be left unlocked, unlike the Knott coupling.
My swallow supplied trailer is probably no more than two years old?
After a little research i have purchased from ebay seller, meadow rover, item number 371312131702.
£8.85. Replacement lock with four keys.
I easily fitted this in 30 mins. No modifications necessary, but you would need a sturdy drift punch!
Obviously I have no connection to seller and this is in no way an ad!
