He was one of the last members to bear a family name that is documented to have become extinct in modern times (the last male died in 1985).
Together they conceived a design for an ingenious lorry, called the "Freighter", and built the prototype in Harry's barn.
During this time, the company made buses, refuse collection vehicles and fork lift trucks, as well as trailers, miniature submarines and other items for the Second World War.
His home in Pixmore Way, Letchworth, was a mock-Tudor house built for him, named Melverley, where he lived until his death, surrounded by armour and swords.
Mr. Shelvoke apparently drove the ex-Prince of Wales' Daimler Double Six motor car.
[2] He also celebrated his supposed family connection to the Shropshire privateer and pirate George Shelvocke (c. 1675-1742),[2] who inspired Coleridge's The Rime of the Ancient Mariner poem.
James Shelvoke (originally Shilvock), Harry's grandfather, (born by 1814, location unknown) headed the family centred in nearby West Bromwich and Aston, part of Birmingham.
His brother Frank also married in Croydon, in 1911, and had one daughter, Barbara Mary (1914-1996/97); she was the last Shelvoke born.
A genetic tendency towards more girls than boys, combined with several males having no children, are the causes of the rareness and then extinction of the family name.