Thank you for your comments, it made me re-read both the MOL book and Lesley Jackson's. Your statement that "These are definitely known as Horizontal optic ribbed vases" is only true if you read Jackson, the MOL team, using what one would persume offical Whitefriar jargon gleaned from the records they now hold, talk about "Heavy optic ribbed" so I guess either description would be acceptable - although my earlier one is flawed and please forget that :oops: .
I am confused :? Who made a reference to page 291 of the MOL book in this thread? That shows some of the Wealdstone range made for Wuidart and if you claim that the ribbing on those vases can be felt on the outside then your reference does not seem to apply to Nic's vase and the one I have, where the ribbing can be felt on the inside as described in both books. If you need a reference to heavy optic ribbed vases in the MOL book, then try page 302, plate 509, and 6 inch is one of the sizes quoted.
Colour is a problem though as the only blue quoted in the catalogue plate 509 is sapphire blue which is by WF standards usually a lot lighter than Nics vase. But of course note the date, 1940, it is surprising that WF were still making coloured glass during the war, and maybe they could obtain supplies to make Saphire Blue but not Sanctuary Blue. Having looked at Jackson's book why do you say the colour of Nic's vase is not Sanctuary Blue? The examples shown in Jackson of Sanctuary Blue look to me very similar to the photos on this thread. You must allow for inaccuracies in colour reproduction in both the book and photos displayed on any website.
Another contender could be royal Blue - but we are back to the Wealdstone range again :roll:
looking forward to more enlightenment.