Securing a Folding Boat Trailer to Drawbar

Good Afternoon All,

I am new to the forum and have need of your wealth of knowledge with a problem I have.

I recently purchased a second hand Flip N Easy along with a cartopper. The seller supplied the brackets but do you think I can work out how to secure the trailer to the draw bar securely.

It has a bracket which appears to sit on the folded lengths of the trailer. There are 2 long J bolts. Despite my best efforts the whole thing just slips back and forth on my camper trailer's draw bar. Not the best solution given some of the roads I plan to be traveling on.

I contacted the manufacturer which was a waste of a phone call.

Regards Tony

Any help, especially pictures would be appreciated