What about one of those big old hydraulic winches that utility companies used? You can get them on ebay for less than £350. I picked one up myself for £250. I havn't got round to fitting it yet, but it looks pretty heavy duty to me. Perhaps worth considering if you don't mind adding 100kg or so to your Landy.
they are built for hard work - but when something breaks or wears out where do you go for spares ?
......... peeps do appear to be quite adverse to a bit of manual labour - Tirfors arent that hard work