Before you bid for a van on ebay, especially if, like me you cover high mileages and have a dodgy back, make sure you sit in and drive a similar model. BEFORE BIDDING. I have driven a number of vans and all for around 40,000 miles per year. Some leave you crippled after a long journey, others don't, The worse vehicle I have driven for back comfort is the Citroen C15; the best is my current Renault Kangoo. The difference being that after a day driving the C15, I had to rest up for a day and with the Renault, I can work the following day.

The lower part of the back rest should give some support and the squab should give a bit of support to thighs and not make it easy to slide down in the seat so there is a gap between your lower back and the seat.

Sit in and get a feel for a similar vehicle before you commit to buy it.