Gas & Water Filler in d-pillar

[CrickCampers]

I'm looking at fitting Gas and water fillers externally behind the little flaps below the rear lights on a Tailgate LWB. I've seen it done when browsing on the forum, but can't find it now. Has anyone done this? and what advice.

 

[Northern Monkey]

Some info here mate
Random Question About Creating Exterior Access.