Images from The National Archives at Kew now attached, and as can be seen 794358 from 10th July 1934 was allocated to CLASS IV as suggested. Of the thirteen CLASSES which the Board of Trade set up to accommodate various materials used by British manufacturers, CLASS IV was dedicated to Earthenware, so why this glass design ended up there I've no idea, other than the old, and much earlier suggestion of some subterfuge by Registrants to hide their inventions from competitors - speculation only of course.
As can be seen, the metal components are absent from the original factory drawing, so this Registration appears to have been confined to the design of the glass body only.
Should the Register entry (BT 53/68) be less then legible, it reads:-
""No. 794358 / CLASS 4 / Date of Registration 10th July 1934. /
John William Sutcliff, (British Subject) 10/14, Charterhouse Street, London, E.C.1.
Address for Service:- as above
4th February 1935. In pursuance of an application received on the 17th December 1934. Leonards Products Limited of 110, Cannon Street, London E.C.4. Registered as proprietors by virtue of a deed dated 26th November 1934 and made between John William Sutcliffe of the one part and Leonards Products Limited of the other part.
Address for service:- as assignees, as above.
9th August 1939 Time for payment of extension fee enlarged until 10th August 1939.
9th August 1939, COPYRIGHT EXTENDED FOR SECOND PERIOD OF FIVE YEARS
Copyright expired 20th July 1944""
At least that's what I think it says - but it means nothing to me, so leave it to others better informed to perhaps put some flesh on the bones.