Welcome. From the buying advice sheet you'll gather that rust corrosion is something you will need to be especially vigilant about especially if it's been in the UK a while. Not mentioned (or else i missed it) but V6 needs watching for noisy cam followers and leaking camshaft seals, the latter being least expensive on labour cost to fix while the expensive cambelt change is being done. The suggested values should be used only as a rough guide as what you really want is a cherished vehicle, even if mileage is a bit high and welding has had to be done: good quality welding may be worth a lot more than no welding
I'd also take the fuel consumption figures with a pinch of salt. 4wd diesel does 2mpg less on average than 2wd diesel. And my 2wd diesel could go below 20mpg on short winter runs (and all cars suffer plummeting mpg in those circumstances, to be fair). I've not heard of a 2 litre petrol achieving 35mpg either, though maybe it has been done.
Out of interest, why a Bongo? There are alternative small campers like Toyota Regius, Toyota Alphard, Nissan Elgrand, Honda Stepwagon, though only the Bongo offers an electric lifting roof model. We love our Bongos but even my Bongo mechanic insists the Toyotas fare much better when it comes to corrosion, and their motors are said to be bullet proof.
The golden rule with these old cars i think is don't allow yourself to be rushed by desperation to hit the road and get camping. Take your time, do your research, and inspect and test drive lots. The chase is fun and you'll soon develop a feel for what is a good (and bad - in hindsight, the first Bongo i test drove was a smelly dog) Bongo /camper van.
