I have located a "Drop Receiver Mount" manufactured by Couplemate Trailer Parts, Part Number CM252 and rated at 3500 kg. It comes complete with towball.
As I wanted to raise the towball, I verified with Couplemate that the receiver mount could be installed raised and not dropped down. Confirmed that it was all OK. Tow ball now sits higher and caravan is level.
Cost for this mount was $60.
Best wishes
Bruce

