Why are the RAF there, recruiting party?
Probably, one of the officers (Flying Officer?) with the navigator's brevet is Afro/Caribbean.
My late next door neighbour from Jamaica was an LAC during WW2 and was discharged home in 1946, he came back on the Windrush in 1948/49 and immediately re-enlisted in the RAF and finished his time as a Cpl.
Apparently re-enlistments in the RAF were quite popular amongst these blokes for whatever reason.