Squid, legally i'm still only able to carry 350kgs cos i haven't put brakes on it yet but a few weeks back i had exactly 1 tonne of timber flooring in it and it did it no worries it was just a bit bouncy but the shocks should have that sorted now.
I have no idea how much weight you'll be able to carry but two tonne payload seem a lot for a 7x4 trailer, so realisticly you could be looking at 2.5t gvm, personally if i was to build a trailer to carry that sort of weight it would definatly be tandem axle as they are so much more stable.