Rear Overhang – Must not exceed the front load space.  There is no definition of ‘front load space’, but one can assume that it is the ‘load space’ portion in front of the axle. As compared to the portion behind the axle, which is the ‘rear overhang’…  So what this is saying is that there must be more of the ‘box’ on the box trailer, to the rear of the wheels, than at the front of the wheels..

Ground Clearance – Within 1 meter on front and back of the wheels, must not be less than 100mm ground clearance, excepting the wheels, tyres, and wheel hubs.

And that’s all she wrote, as far as regulations relating to *getting the trailer registered* go.  The only other caveat is that the trailer must be build ‘fit for purpose’.  I.e. don’t use weak materials and ‘hope it will do’..