When reversing a trailer or caravan with auto reverse brakes let the brakes go off before reversing. In other words, when you stop going forward move slightly forward after you have stopped and this allows the brakes to come off completely. then reverse slowly and the brakes will not come on,i.e. the auto reverse will work as it is designed to do.When you think about it, the brakes are on when you stop and will remain on without that forward movement to allow them to revert to the off position. Hope this solves your problem and saves on brake linings and clutch plates.
The brakes are adjusted too tight, therefore not allowing the reverse cam to fall back. The brakes should be adjusted so that when you pull the lever up one click you can just feel drag on the wheel remember only turn forward when making any adjustments.
Are you sure that your van has an automatic reversing facility? I don't know much about Freedom Caravans, but I don't believe they have either an Alco or Winterhoff chassis. I know that on older model vans you had to "flick a level" on the hitch to reverse. Perhaps you should get in touch with Freedom in Stafford and ask their advise.