From time to time, here is some planning content that provides a design and a critical appraisal framework.
The now archived document ‘Shopfronts’ from London Borough of Hillingdon has some good guidance on Shopfront Design.
In section 8.5 Advertisements Advertisements are defined as the fascia, lettering, any signage within the ‘signable area’ and above this in the upper floors of buildings, and posters and advertising materials affixed to windows.

Fig 1 Shows Acceptable Examples of corporate lettering
adapted to suit its position.