He then went on to Street George’s Hospital Medical School where he qualified in 1933. He joined the Royal Navy as a surgeon-lieutenant in April 1935. He became second medical officer in HMS Valiant on the Mediterranean Station before becoming flotilla medical officer in HMS Grenville in December 1936 and then being posted to HMS Ganges in 1938.
He joined HMS Nelson in April 1940, initially as medical officer and then as principal medical officer
He became a medical specialist at RNH Plymouth in March 1942 and maintained an interest in the use of mass miniature radiography in the diagnosis of diseases of the chest. He was appointed medical specialist at RNH Simonstown, Cape of Good Hope, in 1944.
He became an assistant to the medical director general (naval) in 1948. He became principal medical officer of the submarine base HMS Dolphin and flotilla medical officer to the flag officer (submarines) in 1957 before being appointed as senior specialist in charge of the medicine section at Registered Nurse Hospital Haslar later that year.
He became assistant to the medical director general (naval) again in 1960 and then medical adviser to the Commander-in-Chief, Portsmouth and medical officer in charge of RNH Haslar in 1963.
Holford worked for the Ministry of Health from 1965 to 1974, latterly as senior principal medical officer 1935: surgeon lieutenant 1940: surgeon lieutenant commander 1946: surgeon commander 1957: surgeon captain 1963: surgeon rear admiral 1965: retired Bachelor Cantab (1930).