Having a bit of wireless engineering background myself, your picture made me curious about the radio.
So I looked it up!
"Wireless Set No. 18 was a man pack transmitter-receiver developed in 1940 for short range communication in forward areas between Battalion HQ and Company HQ. Frequency range 6-9MHz. MO control. RF output 0.25W. R/T, CW. Range up to 10 miles. Wireless Set No. 68 was similar but with different frequency range, crystal control option and minor mechanical changes.
Under normal conditions the No. 18 Set was powered by a combined dry battery pack known as "battle battery", which was carried inside the set.
It incorporated a vibratory unit for HT (Hand transceivers) and GB (not sure what GB is), driven from a 6V lead acid 14Ah accumulator which was tapped at 4 volts for LT filament voltage. Whilst operating the set, the accumulator was float charged by the hand cranked generator."
(From the website - WIRELESS FOR THE WARRIOR, http://www.wftw.nl/wireless18.html)