VW Crafter MWB build from new

Hi I’m Tim newbie van build

I’m converting a new VW Crafter into a 2 birth, fixed bulkhead camper with L shaped rear seating, lippert bed lift, sideways drop down with side flares.

I’m 10 months into the build and just getting to the final construction of the kitchen and rear seating units, as I work full time it’s a weekend and evenings project - hence 10 months!

Can anyone give advice on how to get LPG system tested, I have underslung tank, Truma 4e combi and 2 burner hob.