[5] Manners was educated at Ferndown School,[6] before attending Britannia Royal Naval College as a cadet from the age of 13, following in a family tradition of studying in Dartmouth, Devon.

[4][7] He was allowed by the navy to play county cricket for Hampshire in August, making his debut in first-class cricket against Gloucestershire at the United Services Ground in the County Championship,[5][10] scoring 81 runs in his first innings before he was dismissed by Reg Sinfield and thus falling short of becoming the first Hampshire batsman to make a century on first-class debut.

[5] Prior to war being declared, Manners was serving as a watch-keeping officer aboard HMS Birmingham at China Station in Hong Kong.

[3][19] Returning to Southampton in early January 1940, Manners spent a month on leave at the family home at Alverstoke,[20] before being assigned to the destroyer HMS Eglinton which was under construction at the Walker Yard on the Tyne in Newcastle.

[3] Manners was not one of the officers based at Newcastle to be sent to assist with the Dunkirk evacuation and spent the summer escorting convoys down the east coast following the Eglinton's commissioning.

The couple married in October 1940 at Marylebone and narrowly avoided being killed on their wedding night when a German bomb hit the Hyde Park Hotel when they were in its restaurant, but failed to detonate.

After a few weeks commanding Fame, Manners was sent to HMS Eskimo at Falmouth, after her first lieutenant, Edward Peregrine Stuart Russell had fallen overboard and drowned.

[27][5] Manners was made commanding officer of Eskimo in May 1943, and the ship took part in the Allied invasion of Sicily in July 1943, during which she was bombed and severely damaged.

[5] After a few weeks aboard Viceroy, Manners was seconded to HMS Watchman at Derry, after her captain had fallen ill and an officer with experience was required to replace him.

Viceroy was escorting a convoy on 11 April 1945, when the tanker SS Athelduke which was carrying 12,600 long tons (12,800 t) of molasses was hit by a torpedo from the German submarine U-1274 near the Farne Islands, causing two detonations to rock the ship.

[4] The water being too deep for mines made the cause of the explosions a submarine's torpedoes: realising the convoy was under attack from a U-boat, he turned the ship to port and took off in pursuit, obtaining a contact at 2,200 yards (1.3 miles).

Manners commanded an urgent attack with depth charges set to "shallow", the detonation of which temporarily knocked out the electrics aboard Viceroy.

Reckoning that the U-boat had been sunk at a depth of 250 metres (820 ft), a third depth-charge set to "deep" caused a prolonged detonation and brought more oil to the surface.

[5] Once there, the kill was confirmed by further exploratory charges which were dropped and bought to the surface wreckage, documents, and a grey cylinder containing 72 bottles of brandy made in Heilbronn.

[29][30][5] His younger brother, Sherard, also served in the Royal Navy during the war and was awarded the DSC on the same page of the London Gazette for actions undertaken aboard HMS Bedouin whilst escorting a convoy to Malta.

[5] As the war neared its conclusion, Manners took part in Operation Conan, the Royal Navy's contribution to the liberation of Norway following the formal German surrender at Oslo in May 1945.

He was the British naval officer in charge in Trondheim, where he received the German surrender and entertained Crown Prince Olav aboard Viceroy.

[31] Upon leaving Viceroy in July 1945, Manners was assigned to the troop ship RMS Otranto for its voyage to Australia,[4] where he was to be loaned to the Royal Australian Navy.

[10] He returned to sea in 1953, ending his first-class playing days, before retiring from the navy with the rank of lieutenant commander in April 1958 to become the bursar at Dauntsey's School in Wiltshire.

"[7] In November 2019, Manners was presented with a commemorative medal by the Norwegian Defence Attaché John Andreas Olsen for his role as British naval officer in charge of Trondheim during the German surrender in 1945.