Geoff,
Further to reply No 10 by Mack, from his Naval Record:
His number and rate were J55440 Boy II, the J indicating he was in the Seamen and Communications Branch. Occupation - Errand Boy, height on enlistment 5'3/4". He served on HMS Ganges - the Royal Naval Training Establishment Shotley. All boy entrants were trained at HMS Ganges. His record states "Invalided, sequeloca csm (?), mental instability". His conduct and ability had been assessed as Very Good and Moderate.
Charlie