At first sight, this is a pretty straightforward, easy-to-read sign painted at some point during the second half of 1950s or the first half of the 1960s (the style plus two other elements explained below allow to narrow it down to a decade):
Do it Yourself
Elm. 1017 [originally 0641]
"Elm." stands for Elmbridge, the name given to the telephone exchange in Surbiton (this name was adopted because the exchange was located on Elmbridge Avenue and not because Surbiton was part of Elmbridge. Surbiton -which didn't exist in Saxon times- would have been part of the Kingston hundred, not the Elmbridge hundred. The present borough of Elmbridge in Surrey was created on April 1, 1974, nine years after the Municipal Borough of Surbiton merged with Kingston-upon-Thames and a few others municipal boroughs to form the Royal Borough of Kingston upon Thames and was transferred from Surrey to Greater London).
Since the Director System for telephone numbers (three letters and four digits) was replaced by All Figure Numbering in 1966, this sign must have been painted before that date.
A closer look at the wall shows the Stuarts sign was painted over an earlier one:
It is this sign that can be seen partially on a picture taken around 1955 (one third from the left). Thus this picture and the change in the telephone numbering system give us a rough date when the Stuarts sign was painted.
Location: Victoria Road / Picture taken on: 15/04/2008