Leasing the van is not a good idea because at the end of the time you hand back the van and have nothing to show for it. If you go out and buy a van its yours forever. Cost per month is about the same, nothing in it. I looked into it really hard before I bought my van.
Also with leasing you always have to be very wary of the final charge. This happened with taxis, a lot of people started leasing new taxis a few years ago and the deals look good. However, at the end of a lease they charge you for any damage. People were handing back spotless looking taxis but still getting whacked with huge bills for tiny stone chips and really trivial little marks
Whatever you do don't take out a bank loan, about 16% interest. buy a new van from a main agent and their finance is aroud 3-4%, (0% in some cases)
Plus at the moment the dealers are falling over themselves to give you discounts and free extras. We are looking at buying a new car for my wife at the moment, one dealer offered her £3000 off list price without even being asked.