I built a crane to get my gas bottles out as it was cheaper than employing my physiotherapist. It consists of a standard scaffolding jib, a pole, a winch and some clamps to clamp it to the front deck, there is also a socket in the front seats.
Downside, assembly is a bore, the pole itself is a bit on the heavy side and the winch strictly speaking is not cleared for lifting. The picture shows the first winch which was actually a puller, I replaced it with the sort of thing you use to winch a dingy onto a trailer.
It works and I have saved a fortune.
Cheers Graham