He was also a noted philatelist who was a specialist in the stamps and postal history of Great Britain.
In 1928, Dendy Marshall was awarded the Crawford Medal by the Royal Philatelic Society London for his work The British Post Office from its Beginnings to the End of 1925.
[3] Dendy Marshall was a member of the Royal Aeronautical Society and the Institution of Locomotive Engineers.
[5] He died at his home Chinthurst Lodge, Wonersh, in Surrey on 14 June 1945 at age 72.
[2][5] His collection of railway documents and memorabilia was auctioned at Sotheby's on 13 November that same year.