I have no experience of using one, but i there is no way i would. One of the fundamental rules of putting a heavy load in a van, or whatever, is that you keep the weight as low as possible for stability. The expert is not a particularly small van, so i am curious as to why you feel you need one in the 1st place?. I have a flat 500l tank (L 1000mm, W 920mm, H 620mm) in my connect lwb, there is a plastic fish box on top of the tank for all my bits and pieces, poles are on the sides or hanging from the roof, reel is behind the tank, and i have no space issues. I would always recommend a flat tank over an upright one, but if you really felt you needed more space, a normal upright tank would be a better idea than a saddle tank. An upright (baffled) 250l tank is only 325mm wide (1100mm long, 865mm tall), if you had that across the front of your load bay, it would leave plenty of space behind it. Btw, 250l is way too small for me, so i am assuming you are trad, and use wfp for certain jobs?.