As Bernie says, Margaret is no longer on the forum. This was posted before I joined, but maybe the info will be of interest to others. From directories:
1839-41 Cox & Luckman, plane & tool manufacturers, fire . Darwin street
1845-1849 Cox & Luckman, plane & tool manufacturers, fire iron & fender makers, Darwin street
1855-73 Cox & Luckman, manufrs. of fire irons, iron bedsteads, counter weighing machines & planes, 11 Ryland st
1876-1879 , Cox, Luckman & Son. Fire iron manfs, Ryland St
1882-1884 Cox, Luckman & Son. Fire iron mans. &c. 24 Stanhope street, Highgate
1888-1890 Cox, Luckman & Son.(est 1835) Manufs of Fire irons, fire brasses, carpenters and joiners planes,emery cloth & glass paper, 19-29 Stanhope st
1892-1895 Cox, Luckman & Son. Manufs of Fire irons, kitchen pokers & rakes, fire brasses, brass dogs, brass curbs and other fenders , carpenters and joiners planes, counter weighing machines ,19-29 Stanhope st
1897 Cox, Luckman & Son. Manufs of Fire irons, fire brasses, brass dogs, brass curbs, carpenters and joiners planes, , 19-29 Stanhope st
1899 Cox & Luckman Fireron makers, 19 Stanhope St
1900-1913 Cox & Luckman Fireron makers 89½ Gooch St
1915 Cox & Luckman firea-iron makers 250½ Bradford St
Not listed 1921
Mike