Although not stated in his records it is possible that the senior officers of the Royal Marines felt that Harold Ozanne had been through enough. He was home on leave in January 1918 having relinquished command of 1RMLI after Passchendaele and a note on his records dated 16 Jan 1918 states that he was to be 'Struck off the strength of 1st Royal Marine Battalion. Services required by the Admiralty on expiration of leave to UK.'
After the War the Royal Marines total strength was reduced from 55,000 down to 9,500 and there was even a suggestion the whole Corps should be scrapped. There was huge pressure from the Treasury to reduce manpower and costs.
Harold Ozanne had become Brigade Major at Chatham in 1918 and he stayed there for 3 years. He then did an 8 month stint in Ireland followed by 18 months at various land based training establishments such as HMS Impregnable (the old HMS Black Prince) in Plymouth.
In 1924 he was given command of the Royal Marines School of Music in Eastney, Portsmouth. By this time the Marines were providing all the bands throughout the Royal Navy.
In 1927 was put onto half pay and in May 1929 he was 'Placed on the Retired List' at has own request.