Colin, what are you towing ?, i ask as you have stated that you need your hitch to weigh 75 kg's which is about average. we tow a ace twin axle van and easily get 85 kgs nose weight with two 7 kg gas bottles both toilet fluids, two pumps, and the extra tv aerial in the front locker. i would easily get to 75 kg by removing just the fluids and pumps, my battery is also right at the front of the van which does seem a bit silly really it should be over the wheels due to its weight. I know single axles can be a bit harder to balance but i would not have thought any van was so hard to get down to 75kg's.
As a rule i put both my (empty) aqua rolls and my wastemaster in the rear bathroom and the awning goes right over the axle and we balance a perfect 85kg.