If your buying used, even from a forecourt always get it HPI checked.
When I was looking for a van I almost bought a Merc Vito, from a dealer, I had looked at lots in previous weeks and this one looked imaculate - too imaculate actually.
I rang HPI right there on the forecourt, it turned out to have been clocked by about 100.000 miles if I remember right and finance outstanding via daimler benz
and honestly you could have eaten your lunch off the engine and both inside and outside was spotless.
For about £30 its worth it.
Paul Kinder Clean