Bradley coupling is rated upto 1400kgs, this isnt the load rating for the trailer, it will be on a seperate plate, usually on the drawbar.
Tyres are only rated for 487kgs each giving a total of 974kg, given that the trailer will weigh 300kg ish, they are very under rated for your rig.
Looks like you will need to change the tyres and the suspension. With a 1400kg hitch,I would guess tha trailer should be plated at 1300kg. I'm not convinced the trailer will be legal for your rib and engine combination.