believed to be

No.J.24153, Ordinary Seaman, Thomas Edwin Seal MANN
Aged 18

Royal Navy, HMS Africa
Killed or died by means other than disease, accident or enemy action on Sunday, 23rd April 1916

Thomas Edwin Seal MANN was born in Denver, Norfolk on 12th January 1898 (Downham, Norfolk Q1-1898 4B:354), son of Frederick James and Harriett MANN (née SEAL).

1901 census...Aged 3, he was at Cotterells Lane, Elsworth with his father Frederick MANN [27] corn miller, born Soham; his mother Harriet [32] born Soham, brothers John [5] born in Soham, and Ernest [2] born in Denver, Norfolk.

1911 census...Aged 13, he was at The Mill, Ashley, with his father, brothers Frederick James ? MANN and Ernest Edward Seal MANN and Arthur Stanley MANN [9] and Harriett Nancy MANN [7] both born in Elsworth. There had been 8 children but 3 had died. His mother was staying with her Soham born parents Dewey and Mary Ann SEAL at Hasse Road, Soham.

His parents later moved again, to 81, King's St., Plymouth.

On the strength of this it can be assumed that the John MANN on the memorial plaque is
his elder brother Frederick John MANN who was killed in France in 1918

He enlisted as a Boy 2nd class at HMS Ganges, the Naval Training shore base at Shotley, nr Ipswich on 13th April 1913. Then training bases HMS Hawke and HMS Pembroke II before joining HMS Africa on 15th April 1914. There was no official crest for HMS Africa.
Given one official cause of his death being as above, "by means other than by accident disease or enemy action" it seems strange that his service records actually show an accidental death, his Navy records show he died in a "coaling accident". has death by illness.
His ship was based in Scapa Flow at the time just prior to moving to Sheerness.
H.M.S. Africa was interesting in that it was the vessel that first launched an aircraft, i.e. the very first aircraft carrier. On the 10th January 1912 Lt. Charles Sampson RN took off in a Short Improved S.27 Seaplane from a platform mounted above the forward 12" gun turret.
Completed in Chatham in November 1906, costing £1.4 million, with a crew of 777, she was a pre Dreadnought battleship, laid down January 1904, completed November 1906, cost £1,420,040. Crew of 777.

Yes ! it is a plane.

Preparing the runway !

HMS Africa without the 'flight deck'

photo: Commonwealth War Graves Commission

Thomas Mann is buried in Queensferry Cemetery, Scotland,, grave 1413

click here to go to the Commonwealth War Graves Commission website for full cemetery/memorial details