going for a used van upto 10k. love the landrover , but 22mpg is hurting 
I would suggest the Toyota Hiace or VW Transporter but you don't see too many of them second hand until they are quite old - usually a sign of a decent van.
If you go for Vivaro/Trafic/Primastar, be aware that there were gearbox issues until the 55 plate and some say that it still hasn't been fixed adequately. The parts can be quite expensive too when other things go wrong.
If the money is borrowable and the loan is affordable, my own feeling is that brand new is best with vans. Get a Hiace and you would be sorted for a decade. In the longer term that would save money because you won't need to have tanks etc. fitted so often.
Although I've never had one, possibly a reasonable alternative is to get the best Transit you can find for that money? They rust a fair bit, sound like a bag of old bolts compared to Vivaros, but at least they don't usually cost a fortune to fix.