well, I'm blowed - shows I need to get out more often - thanks John. Looks to be pattern No. 916 and likely made between 1910 and 1930, though could be a year or two earlier. John, grateful if you will advise the Rd. No. - would be interesting to see the original factory drawing at Kew. Jackson says .... ".... probably designed between 1903 and 1910 ......... produced until early 1930s .........".
I've looked in both the Blue Book and Thompson from c. 1900 and 1910, but not aware of seeing the name Whitefriars. Could be for several reasons, the most likely being that it's hiding under CLASS IV rather than CLASS III which is the usual place for glass - CLASS IV is usually avoided by researchers as it's wood (I forget), but whatever, it's something other than glass.