 His service-wide nickname was "Grumpy"; supposedly after he complained about the noise squadron comrade Douglas Bader made repairing one of his leg prostheses late at night in late 1939.It kept Unwin awake and he let everyone know about it.Another story relates that it was due to his reaction at being left out of the squadron's operations during the Battle of Dunkirk on 26 May 1940, due to a shortage of aircraft.