I received this 144 pp softback at Xmas. A good read.
This is the Times review -

...This uncommonly reflective memoir provides a unique insight into the world of 'Headache', the tactical equivalent of the well-known Enigma. Not only does it add a vital dimension to the picture of intelligence gathering and the position of intelligence personnel in the tactical processes of war at sea, but it is equally eloquent on the impact of war on a bright young man, engaging his wits to defeat both the enemy and the arcane rituals and procedures of the Royal Navy. A significant addition to the literature of the Second World War, The Enigmatic Sailor combines insight with eloquence'.
Times Literary Supplement

Bill