Hi,
There are a number of points that can be made around this series of wares.
1) As far as I'm aware none of the pieces that have come to light over the years relate to shapes produced by W/F's and shown in their catalogues. Of course it's not impossible for a catalogue by them to turn up and confound us all (or prove the point!), but it is unlikely, given the interest in the work by that factory and the research into the archives held at the Museum of London - which suggests that by now something should have come to light.
3) The shape of the bowl that Wolfie has kindly added to the thread is synonymous with a number of makers, but not W/F's; S&W and Czech would be two known sources. (Unfortunately I didn't record the one I had!).
2) The colour is similar to a number of manufacturers, including W/F's and Czech origins.
3) Cutting on turn mould blown items was done by a number of British manufacturers, not to mention other countires, including Czechoslovakia.
4) Most of the cut range by WJ Wilson and Albert Tubby that are catalogued are scarce, but not all. Therefore, the piece that is shown as chalk on a black board in the MoL book on W/F's (which does not appear in the catalogues) may never have been made; or, may have been made for an exhibition, or as a special commission; or, could possibly have been put into production. None of the possible options is clear, however what is clear, is that, to date, no example has been recorded.
5) The chalk drawing gives rise to interpretation, some say that the lines on the cutting represent vertical cutting along one of the faces of the mitre cut. Further, where there are polished roundels it can be interpreted that it is one roundel inside another. The alternative reading of the drawing is that this is shading to give a three dimensional look to what would otherwise be a difficult to read representation. I favour the latter.
6) There are many examples of cutting emanating from Czechoslovakia that include multiple cuts produced by one wheel (it would have a 'serrated' profile) whereas, although there are examples by British manufacturers they are far less frequent - it does include several designs by Keith Murray, therefore we know that S&W used these cutting wheels.
None of the above observations are conclusive in any way, but are proffered to stimulate thought.
Nigel