Of Salisbury Square, Fleet St, London
1871 Living in Market Harborough
1884 Joined John Haddon and Co
1901 A general merchant
1903 of John Haddon and Co, with Frederick Thomas Larder, patent on type composing machines
1904 Patent, with Frederick Thomas Larder, on platen printing machines
1905 Patent with William Henry Dorman of Stafford on wire stitching machines
1905 Patent on printers cabinets, frames and other furniture
1911 Type founder and colonial merchant, living in Camberwell with his wife Amy Catherine Haddon 37, and children John Bayer Haddon 6 and Charles Walter Bayle Haddon 5
1912 With Wilfred Charles Kimber of West Norwood, patent on wiping apparatus for plate printing machines
1913 With Walter Clay Peters, patent relating to cranks for cycles
Pre-WWI Walter Haddon discovered a material he called "Tungstone", which was described as the "next hardest thing to metal", which he used for making the frames and furniture for the standardised type which his firm, John Haddon and Co supplied to the printing trade.
1914-17 Patents with George Constantinesco on means of supplying fuel to internal combustion engines (1914), and on methods of reversing hydraulic transmission systems (1914); on storing and using energy by means of liquids (1915) and transmitting power by fluid wave transmission, on liquid wave transmission (1915), on a method of absorbing the recoil of guns using liquids (1915), and on a rock drill (1915), on synchronous alternating liquid current motors (1916), on apparatus for transmitting pressure between fluid columns and moving surfaces (1916), on liquid wave transmission generator (1917)
Post-WWI: Shared in an award of £15,000 by the Royal Commission on Awards to Inventors in respect of communication to the US government of inventions, designs, etc in relation to aircraft and aircraft accessories, specifically for synchronizing gears
1925 Tungstone Accumulator Co of Salisbury Sq, Fleet St, London, announced a new design of accumulator.
1927 Patent with James McDonald Burnett of Whitstable on accumulator plates (1927)
1933 Patent with William Herbert Exley on control valves for liquid elevators
1936 Patent with George Thomas Baldwin on feeding sheets to printing machines
1938 Obituary 
THE engineering industry, no less than Fleet-street., has lost a leader in business and industry by the death of Mr. Walter Haddon, which occurred on Tuesday, April 5th , in his seventy-third year. Mr. Haddon, who came of an old farming family, was born on December 31st, 1864, at Clipston, near Market Harborough. In 1879 he was apprenticed to the printing trade and served an apprenticeship of five years, entering the firm of John Haddon and Co as a compositor at the age of twenty. He quickly rose to an important position in the firm and made his mark in both the advertising and publishing sides of the firm's busines. He was always keenly attracted to the machinery side of the trade, and was associated with the "point " method of designation of printing types, which is now in general use. At a time when printing types were lacking in standardisation he established his own type foundry at Market Harborough. His first connection with the firm of W. H. Dorman and Co., of Stafford, of which he became at a later date the managing director and chairman, a post which he continued to hold until his death, was about 1910, when he became an agent for a special printing press which was then being made by the firm. Mr. Haddon took a keen interest in the firm, which had for some years specialised in the production of boot and shoe-making machinery and parts, first for the English and American Shoe Machinery Company and later for its successor, the British United Shoe Machinery Company, and later he became interested in the finance and administration of the Dorman undertaking. Shortly before the war Mr. Haddon met Mr. George Constantinesco, of Roumania, and established an experimental laboratory for the study of the wave transmission of power at Alperton, near Ealing. This work led to the "C.C." gear, which was used for synchronous firing through propeller gaps and was freely used during the war. After the war Mr. Haddon acquired the patents for wave transmission for the British Isles and the Dominions, and in articles published in THE ENGINEER of October 27th and November 3rd, 1922, we described some of the practical applications carried out by Messrs. Dorman, and the application of the system to rock drilling. Up to the last he took a keen interest in the firm's work and its road transport and oil engine developments. Walter Haddon was widely known in the printing and publishing trades, and his death will be deeply regretted by a wide circle of business and engineering friends.