Naming Petrol Stations & Banks

There exists a class of retail outlets. best illustrated by Banks and Petrol Stations, where the correct name of the outlet is not the widely used name.

Most bank branches will be known within their parent organisation as XYZ Branch, Huge Banking Corp, and this is usually shown on the name plate outside the branch. A similar situation exists with petrol stations, such as Sheppards Wood Service Station and the Sportsman Filling Station. The former has a big Texaco sign outside and the latter has a Murco sign outside. (It was these two which alerted me to the potential inconsistency in appraoach).

There are numerous other types of shops and food outlets where this applies (e.g., Spar-branded shops, Subway outlets etc.)

So far it appears that the most widely used convention for naming such outlets on OSM is to use the obvious trading name - UBS, Lloyds-TSB, Deutsche Bank, Shell, BP, Esso etc. - in the name tag. In addition the brand tag is available to describe what is known in the retail trade as the "fascia" but this is not always used as well as the name tag with such outlets. Furthermore it is also possible to tag operator to allow for franchise operations such as Subway.

Are there any guidelines as to the best way to approach tagging these situations in such a way as to make tagging simple for mappers, and make the most appropriate information readily available for data consumers?