When you are buying a used van you must make sure you check the paperwork thoroughly, especially for high mileage models, as this can save you a lot of money and hassle later on. Request full service history, MOT certificates and any receipts for works and repairs that have taken place and check these against the owner’s description of the van and its condition. Look at the number of previous owners carefully, as generally people keep vans for quite a few years and a van with a high number of previous owners but low mileage could indicate that it is problematic and people have sold it on to get something more reliable.
Also check the vehicle identification number (VIN) matches the MoT certificates and other paperwork to ensure that the records you have been given relate to the right vehicle.
If you are unhappy with the paperwork for any reasons it would be best to move on and look at other, more reliable options.