That is a fairly steep slope on a (slippery) gravel beach, and the boat appears to be quite substantial in size, in relation to the poor Range Rover - no wonder it had problems!
One professional boat hauler here has a Land Rover which he uses for recovering various speedboats from the sea at Holetown every evening after they have finished working for the day - he does not venture anywhere near the sea with his Land Rover. Rather, he has a stout rope that is made off to a convenient coconut tree - this rope then goes through a large turning block which is attached to the towing eye on the trailer, giving a 2: 1 purchase. The Land Rover stays on hard sand much higher up the beach and with this purchase and method he can recover vessels like the one in the link relatively easily.
There is a concrete slipway just next to the sinking Range rover which they chose not to use. I wonder if they managed to drag it out before the tide covered it completely. Still had its lights on at half tide!
I had a Range Rover once, and was told by a wife of a good friend: "What's the difference between a Range Rover and a hedgehog? Hedgehog's have pricks on the outside....."