Kew reference for the Representations Book is BT 50/89. As is usual with Sowerby, these purple ink drawings are a little meagre and show only two dimensional illustrations, but regret this is the best that can be obtained. It does at least give an idea of the type of lid that Roy is looking for (and probably won't find)
This particular Registration is beyond the diamond lozenge period, which ceased some time in January 1884 - the books for which contained Registrations for glass only (all Class III) - and this separation of one CLASS only per book, was the same for all Classes of goods. So, although they're very large and heavy, the four Representations books that cover all of the images for glass from 1842 to January 1884, do mean that much information is confined within a few volumes only.
Unfortunately, the Board of Trade in their wisdom decided that after January 1884 all goods, no matter what their CLASS, would be Registered from a single series of Nos., and the Representations (the pix) of each article would no longer be contained in separate volumes for each Class. Thus from January 1884 all Classes are together in the same books, and this makes for lean pickings, quite often, from say, just one volume, even though it might contain many hundreds of Registrations.
The Victorians, during the later part of the C19, had a passion for designing wallpaper and cotton fabrics, and the Representations books after Jan 1884 are full to overflowing with such designs, meaning that items of glass are spaced very widely apart.
If you look for example at the early part of 1884, you'll see that Slack notes only six items of glass in over three and a half thousand new Registrations.
Whilst I have almost all pix from the lozenge period it's unlikely - in view of the above - that I'll ever attempt a full library of pix for items post January 1884.
Just a note as always to remind people of our appreciation and thanks to the Trustees of The National Archives for continuing to allow photography and publishing of watermarked pix of glass Registrations on the GMB.