Load Limits on Towbar Tongues?

I need to put a bit of “space” between my Tvan campertrailer and the drop down fridge slide fitted to the rear of my Landcruiser troopy. On a roadside stop where we need to access the fridge, pulling the fridge out and down means that it hits the camper’s spare wheel unless I have been “clever” enough to put a slight angle on when I parked so that the fridge will clear it. Doing so then means that the right hand side door cannot be fully opened :(

I now have access to a longer tow tongue to fit into the towbar which will give me more clearance, however I am now wondering about load limits on these towing tongues. Kaymar have said that they will manufacture one for me, but this tongue seems to do the job.

Can anyone advise me as to how to determine what load the towing tongues are capable of carrying. Whilst the Tvan is not all that heavy (1000 kg fully loaded) the time could come when I want to get into a craavan or similar.
There are no markings or stamps on either the tongue or the towbar that give me a clue. The towbar that this longer tongue came from has been taken off a Holden Commodore.

Thank in advance.