Roy
I have a copy of " The Identification of English Pressd Glass 1842-1902 " by Jenny Thompson, on page 142 it reads, Rd No 92571 30 January 1887 J. Stembridge & Co, Holborn. Importers Pattern table decoration - lamp, not sure if this is of any help unless anyone knows about this importer, nice piece, I collect Davidson from your photo this is in a colour very much like there's without the Rd No my first guess would have been Davidson.
Tony H in NZ