well i've gone full retard...
fitted the shite one, drove to asda yesterday to fill up the LPG, and drove off without refitting that one either. What a fucking muppet!
I will order a good Autogas branded one from one of the stores, and i guess see about fitting a tether or something!
The chat about the square fillers is interesting. My current ones in the bumper, and the bumpers fecked and needs replaced, so theres a possibility to swap it out. I was considering some sort of bracket on the tow hitch where i could fit the filler? I guess i need to investigate swapping it out for a different one when i do the bumper.
The typical way to anchor them onto the towbar (which is the case with the ones I've got, though none of them are a p38) is to use one of the kits like this https://tinleytech.co.uk/shop/lpg-parts/uk-bayonet-filler-90-complete-square-cover/ , and drill two holes for the towbar retaining bolts to go though into the plate. If the Towbar is like the one fitted to the Disco 2 (Which I don't know if it is or isn't the case) then it needs a longer plate than the one supplied in that sort of kit (mine was made out of a spare bit of metal using the plate as a template, but its easy enough to make one without the plate anyway, if your current one will undo from whereever its in place then you would just need the two bits of the plastic cap).
Having lost the cap off mine I tend to put it in my pocket when filling now, as leaving it on top of the bumper is a surefire way to forget it. A tether would be better still, but one of those things I keep meaning to do, but never get round to it.
Other advantage of putting it in the middle is you can fill from either side which is handy, though can be a pain if the hose is particularly short.
Avoid the All ride caps (blue and black packet) those are the first ones I brought to replace the already missing one on the first LPG car I had and are utterly useless.