dont see how you can fit a L5 wrong ,water in water out and gas on a regulator thats the same as any basic bbQ or gass heater,and as for the insurance i still dont see the problem as you are fitting what is classed as a tempory unit as its made for using outside your not acctully moding the van are you?because if thats classed as a mod to the van so must b the complete wfp setup as it is bolted to the floor.mayb i am wrong but if you put the deisel 1 in that is a mod to the van as your bracking into the deisel tank