From a forum I'm involved in (New Zealand). Just passing this on as I have no knowledge of what's really involved
Re: Lowering the axle, lifting the van...
I am never one to assume things, but, with a solar panel fitted, it could only be hooked up to the battery. Is a solar controller fitted? Any idea on the size of the panel? Is the storage under cover or open air?
This may be of help for the awning end fitting. Rig it up with flexible pipe etc.
https://www.amazon.co.uk/halkey-roberts-valve-adapter/s?k=halkey+roberts+valve+adapter
On the awning end, the connection is called a Halkey Roberts connector. I believe they come in two sizes. I have the same fittings on my inflatable boat, a marine shop may help.
I have found that I get black streaky stuff coming out after putting pink in the top tank. Just use water now with a spray bottle of pink in the bathroom. I empty top tank if not using van for more than a month.
Caravan leisure batteries are LiFePO4 (Lithium Iron Phosphate). The fire issues involve Lithium Ion batteries, which are totally different. Have a read: https://www.relionbattery.com/knowledge/how-are-lifepo4-batteries-safer-than-other-lithium-batteries
Could be a worn O ring where the pump plugs in. Replacing it is a matter of a couple of dollars (I'm in NZ) and put a dab of food grade silicon on it...Peter
Rolling it clockwise (as viewed from the front of the van) enables you to partly open the awning. I think you unroll it 6 turns and you may need the mounting blocks fitted to the side of the caravan, this is for models 3.6M or larger....Peter