According to the Baker & Crowe list, Registration 851364 was the final design from Jobling that the factory recorded with the Board of Trade. As mentioned, there isn't a factory catalogue No. …………… unfortunately, I omitted to mention that these final two designs - the mermaid lighting bowl and this iris lighting bowl - for whatever reason - had their BoT design protection extended for an additional period of five years. Thus - protection for 849494 which was Registered originally on 03.12.1946 expired finally on 03.12.1956 …………...… and 851364 first Registered on 12.06.1947 lost its protection on 12.06.1957 - possibly these were both successful designs and the company thought they warranted protection for longer, but that's just speculation.
In the course of searching TNA records for Jobling Registered designs, I wasn't aware of seeing any of the factory's designs which the authors list as being without Registered status - so those seventeen items remain unknown in the Kew archives, for whatever reason - they may well never have been there in the first place.
pix attached of Reg. 851364 - again, the extent of the design, in relief, is quite substantial. Apologies for the glare, but think we'd all agree this is a beautiful design.