LRDG Wireless set up

[Charlie Down]

Ok. Found these LRDG Documents, I think originally marked 'TOP SECRET'.
So they used 2 standard 6 volt truck batteries, one from the truck and one mounted next to it on the side step. They were used in series for wireless operation and in parallel for charging, via a 'special series Parallel switch'. The trucks generator charged the batteries and if on road watch for several days batteries were swapped with batteries from another truck. This required no chore horse charging set.
The second document shows the maintenance procedure for the wireless equipment in the field.
So does that mean the panel only needed one knife switch, and they used a standard 4 switch panel and removed the other 3 knife switches, or a 2 knife switch panel with a knife switch removed? The 2 positions of the switch would be series and parallel.
Looking at the attached compilation of switch panels I think I'm leaning towards a 2 switch panel with one switch removed.
Also what is involved with setting a truck up to be wireless suppressed?
Could the photo at the start be another truck waiting to swap batteries, based on this new information?