If you can have such a thing as 'colour snobbery' - I'd certainly be guilty - the amethyst is my favourite, followed closely by blue. I find it hard to believe that a book entitled 'Bristol Glass" doesn't actually show any examples of Bristol green - I'd say it was vastly more than "a shame" - postively ludicrous in fact, assuming it is the book's intention to discuss 'Bristol' coloured glass. I don't have the book, but think on this evidence I'd give it a miss.
My only book on coloured glass is something called, appropriately, 'Coloured Glass' by Derick C. Davis and Keith Middlemas - bit dated at 1968, but packed with good illustrations, although not qualified to say if the text is accurate. There is, apparently, something called 'British and other Coloured Glass' by John Bedford - 1954, but haven't a clue as to its usefulness.
Apparently the blue was arrived at by the use of smalt - a vitreous form of cobalt oxide, which presumably was imported, but from where I don't know and, occasionally, copper was used for blue.
The greens seem to vary more than the others, especially in the drinking glasses - loads of shades.
Sorry for the sidetracking Keith - and seems you have a lot more to go yet