The deacon is not a tank, a tank MUST have tracks in order to be classified as a tank. The vickers 6-ton was only used by the UK as a training tank, and they only had 4. The Mark VIII A25 did not see combat, and none were put into service. The Centurion was not in service in 1945, only in 1946 and onward. Including the M4 Sherman suggests that all the lend-lease vehicles would be on the quiz, which they are not, probably because they were American and not British. The Medium Tank Mark 2 is an unnecessary mention as it did not see action in WW2 and were in low numbers as production of them had stopped before 1939.