The building this sign is painted on, at 51 Silver Street, appears on a picture taken c 1955. Unfortunately the picture is too small and by then the sign had already badly faded (it is on the third building from the right, on the side wall between the top of the street light and the chimneys).
Old directories available online don't offer much help either, except maybe Kelly's Directory of the Leather Trades, published in 1880. Indeed under "Boot & Shoe Manufacturers - Wholesale" it lists James and William Moore, of Crispin House, Fisherton Street and 51 Silver Street. It is possible that some of the letters painted at some point just below the moulded stone cornice spellt "Moore". It may also be my imagination.
Location: Silver Street, Salisbury, Wiltshire / Picture taken on: 09/08/2009