It is Mattiello, Viv. Joseph Mattiello & Son,. In 1932,1933 Kellys he is at 6 Duddeston Row , but listed just as Sheet metal worker , but without the "& Son". In the 1936 Kellys he is at 50 Duddeston Row, listed as Joseph Mattiello & Son, tinsmith. So the photo would have been taken (allowing for the delay in publication of Kellys, usually taken as year before publication), between 1932 and 1935
The "& Son" does look a bit cramped and different at the end, which would agree to it having been added