MD5ADZ 1956 Egypt

This is a card from an operation 11-19 December 1956, by three operators - the calls MD5ADZ, MD5AMO, MD5DNQ, from 11 -19 December 1956.
The emblem on the card is that of the British Royal Signals.
The Suez Canal Zone effectively ceased in March 1956, when the last of the British forces left, and if you read it up they would have been unlikely to want to return in a hurry.
These calls are all three letter suffixes. All previous MD5 calls had two letter suffixes.
Who issued the license?
Who were the operators?
What was the significance of the trip?

G4UZN Collection