Tbh for your intended used id just get a single axel galvanised trailer off ebay – brand new ones on there for about 600 quid. The guy will plate it to what you need
My dads been rocking a twin axel 750kg plated ome for trade use for the last 5 years – heavy use and abuse every day in that period – cost 1k and earned its money many times over.
Its being replaced with an ifor now but for occasional home use id have no qualms in buying one – infact im having his old one when he gets the ifor – the chassis on his is still sound just some of the body needs a bit of tlc with the mig.
Main reason he didnt go ifor at first is because his van was too small to pull the ifor that could fit the size of sheet material he wanted on the flat bottom , has a bigger engined van now