Thanks to all of you, it is wonderful when others can do the ID bit.Please note: I must make it clear that the UK use of the name "bullet", for these vases is causing problems, as that translates to the French "Boule" which these vases are definitely not, of that pattern, also by Schrötter. This has been remarked on as a potential source of problems by Ing Siegmar Geiselberger, of www.pressglas-korrespondenz.de, and we may need to find a less-potentially confusing name or number for these vases.
Re colours, I'm not sure what the reasons are why certain colours are more common than others. I am aware that materials shortages from time to time meant that occasionally, items that were made in coloured glass, were produced anyway, just to satisfy demand. These I have seen in several countries, including the UK, in flint, so I would not be prepared to make any comment on colour scarcity. Unlike Whitefriars, there does not appear to be records of pieces by day, or how many in which colour.
I have heard idle chatter, that cobalt blue is scarce, but that is one of the colours Bohemia is best known for, and used at most major glass-works, so I personally would not give that much credence.
Certain items were only made in flint, but many have turned out to be made in wide ranges of colour.
I would advise people not to get carried away with notions of greater value for allegedly scarce colours. Why?
The Sklo Union factories made thousands of pieces a day in pressed glass. Even when glass colourants were in short supply, and the colour of the batch varied slightly, they still made thousands of pieces.
The one aspect of this that David makes, regarding importers, is that there does appear to be a sign that clear versions of patterns had well-defined markets. I am still exploring this as I write, so it would be pre-mature to expand on this at the moment.