Looks nice, Warren. As others have said, it's probably a GS rather than a GX. The GX is a bit of a "pov pack" model, so you'd want to check that it has all the goodies you might want - like A/C, elec windows all round, 3 diff-locks etc. If any of those items aren't working 100% then you're looking at knocking big chunks off that asking price. Don't buy any stories about A/C needing regassing - if it JUST needed regassing, they would have done it! A/C compressors are serious money and they do seem to pack up through lack of regular use in the UK.
The cloth seats probably aren't a big deal - throw decent seat covers on when you get to SA and it doesn't matter whether they're cloth or leather underneath.
I'm sure you've got your check-list - at that mileage, it may well be running it's original CVs etc, so check for excessive CV wear by driving it slowly in a tight circle with the CD locked (i.e. in low range) with the window open. If the CVs chatter, then knock another £500+ off the price as OEM replacements are £££.
If everything checks out ok, that truck will be a good buy!