If the OTL, Melville track, Jeannie track etc cant unhitch our 4m boat trailer with ball then Im not exactly sure what real world scenario can.

Maybe its the 130 long wheel base combined with long distance between hitch and axle
Maybe Im just lucky
Maybe Ive just jinxed myself and its gonna fall off next time we go north? Oh well thats what the chains are for - im sure as not gonna spend $250 on a bush trailer!

Steve