The last sentence in the link says-
"You can view the rating of a food business by checking the sticker in the window, the certificate on display inside the premises or by going to the Food Standard Agency's website at
www.food.gov.uk/ratings."
Surely the premises should be obliged to display the rating in the window. Quite often the certificate inside is hard to find, if displayed at all! If they are obliged to display it then action should be taken if they don't.
Terry