Thank you, Paul and Sid, for your inputs.
My original query was posted to help me with a project I am pursuing in association with helping to build the GMB RD numbers photo database.
As Paul indicates, Simon Cottle (in ‘Sowerby – Gateshead Glass’ , Tyne and Wear Museum Services, 1986) shows some Sowerby pattern numbers alongside the RD numbers, but that the list is far from complete, and only the Sowerby pattern book IX (1882) is illustrated as an entity with drawings of the pieces with their the pattern numbers. The pattern book IX (1882) illustrations do not indicate which of the pattern numbers relate to registered designs, and a few of the Cottle list pattern number references are to pattern books VIII and XI (neither of which is illustrated in the book).
From the other angle, the Thistlewood Sowerby CD-ROM catalogues usually show the Sowerby pieces with their pattern numbers, but rarely with the corresponding RD numbers. Not surprisngly, the list of Sowerby pattern numbers in CD-ROM Volume 3 is far from complete, and only some have photographs associated. As you both say, the ‘nominal’ registration lozenge motif alongside the pattern numbers in the various pattern books is useful as an indicator of a design registration, but no real use in providing precise registration details
So, to fill in some of the gaps in both these important references, I’m currently beginning to build a separate database linking Sowerby RD numbers with their Sowerby pattern book numbers, and also trying to muster representative photographs of the relevant pieces showing as many size, shape and variations as possible, thereby filling in some of the gaps in both Cottle’s book and the Thistlewood Sowerby CD-ROMs.
At the same time, I’m also trying to assemble a collection of photos assigning Sowerby pattern numbers to unregistered designs.
Please bear with me, therefore, if there seem to be a lot of my topics posted in this section regarding links between Sowerby registrations and their pattern book numbers. I hope to be able to collate what details I currently have with photos on three related photo galleries with open access for all in the near future.