Fixing trailer number plate to trailer...

With those clips you have bought, I think you put the bottom of the number pate in the little rolled lip at the bottom of it, and where the bolt goes through the numberplate, you screw it into the larger hole, and then you attach it to your trailer via screws at the top.

That's what I got from looking at it anyway. Why not phone the company and ask?
 
Another vote for velcro strips except got mine from Staples!! Have done this for the last three years no probs and it's dead easy if you need to change the reg plate.
 
Velcro sticky spots. One side one trailer one side on number plate - plus if you change towing vehicle, easy to change number placte. Mine has been attached like this for 6 years, never come off.
 
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