Santa,
The wonder of glass is, of course, is within its very nature plastic and malleable, capable of transformation into a huge variety of forms and colours whether in the expert hands of the artisan or artist, or by industrial processes enabling mass production.
Although I appreciate many kinds of glass for their intrinsic style, beauty or usefulness, I like to be able to compare one piece with another and, in my case, relate or classify them stylistically, historically or technically. I think most people who appreciate glass for any number reasons like to know how a piece was made, who made it, and when it was likely to have been made.
Begun in 1842, British design registrations were primarily a means of providing copyright protection for a (supposedly) unique design feature sometimes the shape of a piece, sometimes the decoration (or part of the decoration) on a piece, and sometimes the combination of the two. The protection was for a fixed period of time, and could be renewed. From my point of view though, if a glass item bears British design registration details (be it a registry date lozenge or design registration number) then that provides many of my requirements for placing it reliably (or even precisely) within in a stylistic, historical, chronological, or technical classification, namely:
The design registrant, who was often, but not always, the manufacturer of the item. For some items, the design was registered by an agent or importer on behalf of a manufacturer; sometimes the registrant was the actual designer of copyright owner of the design. The actual registers also give the address of the registrant.
The registration date day, month and year.
The registered design number, enabling (in theory) a precise location for the details within the registers (and also a cross reference to the design representation - a pictorial representation, normally a drawing or photograph, of the registered unique design feature).
I have a strong interest in British glass made broadly during the period just overlapping Queen Victorias reign (say 1835-1910), especially the history of glass manufacture during that period and the developing social and artistic implications of the availability of affordable, mass-produced, factory-made glassware.
Fortunately, the GMB has proved to be the ideal forum for resolving many of my queries, and hopefully other like-minded members have also benefited from the interchange of information that it provides.
Fred.