Jacob Simon provides a full biography: Izod was the son of James and Hannah Izod, was married twice, firstly in 1858 and then in 1861 to Susan Gray. In the 1881 census Edwin W. Izod, age 43, was living at 64 Albany St with his wife Susan and six children. In 1891 the family was living in Fulham Road, and included a son George Joseph, a picture restorer, age 26. They traded in partnership 1895-1897 (London Gazette, 7 January 1898). In the 1901 census Edwin Izod was recorded at 4 Colosseum Terrace, Regents Park, as a retired art dealer. It is not entirely clear whether Edwin or George Joseph was the tradesman that Whistler favoured.
Jacob Simon summarises the firm as follows: 'Edwin William Izod 1872-1896, E.W. Izod & Son 1897-1898, Izod & Co 1899-1915 (advertising as Izod & Son 1908-1910). At 64 Albany St, Regent’s Park, London 1872-1888, 220 Great Portland St 1889-1909, 20 and 22 Maddox St, Bond St 1909-1913, 6 Maddox St 1910, 124 New Bond St 1914-1915. Picture restorers and dealers.'
On 22 February 1903, Whistler complained to W. S. Marchant of Goupil's that their picture restorer, 'Izod' of Izod & Co., Great Portland Street, had not looked after Arrangement in Brown and Black: Portrait of Miss Rosa Corder y203 personally and there was some bloom under the varnish (GUW #03054).
Simon, Jacob, British picture restorers, 1600-1950, National Portrait Gallery website.