Hi Dave
I had to get one adapted for my needs, however I have not fitted it yet. We do a lot of high end rural properties, and the van back doors are left open. So I have vented the flue out of the back of the van.
The reason I went this route I had to have a bend it the flue to vent through the roof, and this bend restricted the exhaust gases getting away and would trip the sensor on the heater. So by having a less restrictive bend to the back of the van I avoided this problem.
Roy