Getting some photos of RD 810370 ready to add to the GMB RD database, but decided check on the GMB search facility first, and came up with this unresolved thread from 2008.
Can confirm that RD 810370 doen't appear in the 'Blue Book', buthttp://cloudglass.com/ClaytonMayers.htm
shows that RD 810370 was registered by Clayton Mayers & Co. Ltd, North Circular Road, London, N1, on 29 February 1936.
This was Clayton Mayers final glass design registration.
Almost certainly manufactured by Davidson.
The photo links on the opening post no longer work, so I am attaching some photos direct to the GMB as permanent reference. They show champagne saucers and liqueur or sherry glasses, all with a machine-engraved pattern of swags and tails on the bowl (rather in the style of 'Pall Mall' glassware), a plain stem, and a plain circular foot. All are marked with the RD number (acid etched?) on the underside of the foot. The mark is slightly unusual in that it reads 'Regd. Design 810370' rather than the more common 'Rd. No. XXXXXX'.
Does anyone of photos of other glassware shapes from this design, please?