It can only been seen in full from a narrow angle, which doesn't make it easy to read it. The best is to move a bit back, even if the last line is then hidden.
The most recent sign, in light blue letters, could date from the 1920s-30s as R. Gunner is mentioned in a 1931 issue of The Meat trades' journal and cattle salesman's gazette: The organ of the British, colonial, and foreign live stock and dead meat trades. It reads:
The older sign, or maybe signs, is or are more difficult to read:
Scottish & English
Be... [Beef ?]
Grass Fed ...s
Dairy Fed Pork
It looks as if there could be more but the lines ovelap.
Location: Ealing Road / Pictures taken on: 30/07/2010