No picture 'cos I'm not into 45rpm :( Member since Jan 2013 3428 Points Moderator
For those slightly puzzled by this question, you are referring to one of the databases in the UK Dating software in this thread.
In the example you give, everything after the final comma is treated as a comment. I sometimes add comments to clarify unusual or significant entries. In this case, the source for dates (Frank Andrews & Ernie Bayly) says that HMV B-309 to B-491 were added to the catalogue in September 1915 (which was probably the date of issue of the annual catalogue). They seem to represent re-issues of earlier single sided discs in double sided format. In contrast, the previous entry in the database for B-298 to B-307 in September is for recent recordings, and probably represents the September 1915 monthly supplement contents.It also has a comment that B-308 wasn't issued.