Hi as Alistair
has said the box is as suggested i have looked in the workshop manuals and it says the carrier with the 4.6 mortar had the radio and on the TT carrier they used it for rations. but as it has all the fixings for the radio it would look nice.
But one question comes to mind how did they communicate to the gun team and to HQ or how did the infantry contact them perhaps it was just one command carrier between two or three teams ?