Capot :
It's a well-known photograph which has appeared in several places. I believe it was featured as a still in the TV programme made in 1996 for Heathrow's 50th birthday. It also appeared in Propliner magazine. It tends to go with an exterior shot of the same tent, alongside which is the communications centre, namely a group of several traditional red telephone boxes standing at slightly drunken angles as they separately gently subside into the mud all around. Being 1946 my guess also would be that the tents were RAF surplus.
My guess is that it was issued by Heathrow in 1946 as a publicity photo. If your father was actually the photographer that would indeed be a find.