The document that first got me on the road for details on the ramp wagon
http://movcon.org.uk/History/Documents/DID/D-MCHS%200140.htm
Scoll to near the bottom there is a simple diagram showing the axle seperated from the wagon, only side view though but it may help. IT looks like a simple slide held in place with retaining bolts.
On another matter, your green for painting the wagons, up to the point when some fool invented "radar reflective paint", as if that worked, the military used to use a very nice "shiny" green, always shiny can't bull a dull paint. I aways knew it as Mid Bronze Green. The Land Rover dealer may be able to get this, Coded as RTC 4042 T GREEN. That's the expensive way, if you only have a need for one or two vehicles, the other alternative is a day out at one of these vintage military vehicle rallies, theres normally one or two traders selling all the different colours over the years. They normally sell it by the quart, it will need thinning, should out live you, its very stable, but the bronze does collect at the bottom.