I hope the following from IGC might be helpful:

Name William Evans
Other Names William Evans Ltd
Address1 95a Buckingham Palace Road
Address2 4 Holden Terrace, Pimlico
Address3 4 Pall Mall Place
Address4 63 Pall Mall
Address5 67a St James's Street
City/Town London
Country United Kingdom
Trade Gun & rifle maker
Other Address
Dates 1883-date

Notes
William Evans worked for James Purdey for some years prior to 1871, but in that year he joined Harris Holland (Holland & Holland). He was not a qualified gun maker, and it appears he worked in the retail shops of both firms rather than in any workshop. In 1883 he started his own business at 95a Buckingham Palace Road which, despite the name, was not a very prestigious address. Some London makers, such as Purdey, Boss and Holland & Holland, preferred not to sell second-hand guns at that time; they wanted the public to think their guns were so reliable and highly valued that they were passed from father to son and never came on the second-hand market. William Evans thought differently. In 1884 William Evans moved to 4 Holden Terrace, Pimlico, near to Victoria Station, but by 1887 the firm was able to afford to move to 4 Pall Mall Place. This was of great benefit to the firm because of the number of clubs in the area, especially military clubs; the vast majority of men in the services could not afford new guns from Purdey, Holland or Boss, but William Evans could supply new and second-hand guns of English and foreign manufacture in a range of qualities and prices. No separate factory or workshop premises have ever been recorded in the name of the firm, and in their early years up to the mid-1890s they bought completed guns, certainly from Birmingham trade manufacturers and probably from one or two London makers. From the mid-1890s they probably bought guns in-the-white in Birmingham, as did Holland & Holland (prior to the establishment of their own factory in 1893), Churchill, Hellis, and many others. In 1896 the firm moved to 63 Pall Mall. At some time the firm was appointed gunmaker to the Duke of Connaught.

On 3 March 1905 W Evans and W Corrie registered patent No. 4472 for a single trigger mechanism. During the First World War the firm did a certain amount of Government work in particular making-up a number of sniper rifles for the Scots Guards. The post war years were survived by buying bankrupt stock and selling secondhand guns as well as a few good quality guns and rifles.

In 1934 the firm became a limited liability company, William Evans Ltd. In this year J H Thomas represented the company at the funeral of Samuel Robertson of Boss & Co. On 23 February 1944 the Pall Mall premises were bombed and the company was forced to move to its present address at 67a St James's Street.

It is not known when William Evans died, it could well have been in 1934 when he would have been about 73 years of age, but three generations of the Dolden family managed the shop up to the 1980s. In the 1980s the company was sold (to Lord Ramsay / American interests?), and then resold to a consortium.

The records of the company are held at 67a St James's Street.

Other Info
The firm sold cartridges under the names "Pall Mall", "Gastight", "Pegamoid", "Mark Over", "Marlboro" and "Sky High High Velocity".

Tim