There's a place in Bourne that has a load of solar ones not looked closely at them but would imagine they are similar.
I have an old, something like 2006 securicabin, earns good money although Elliots painted it a few years ago which hasn't done it any favours as the paint has expands and contracts it's all cracked, I did give it a quick 5 gallon make over but if I keep it, will at some point bite the bullet and either fill the holes or get it sandblasted re painted. Awful thing to tow but has paid for it's self many times over.
Mine has a battery for the genny and then 2 leisure batteries for the 12v lighting and water pumps for the basins and flushing toilet. 230v water heater which after running for 20 mins or so in the morning has hot water for the majority of the day
As someone said previously new they cost over 20k