David â€” Please be cautious about using the term "Nailsea". There was a glass house at Nailsea, near Bristol, but Hajdamach only uses the term in connection with trailed glass, thus:
Trailed decoration is often termed 'Nailsea' but was made by glasshouses in all parts of the country. ...
"Nailsea" was one of a range of terms used by old-style experts, particularly auctioneers, for "Don't know". Other terms in this category were "Mary Gregory" and "Stourbridge". The problem was that as experts, "Don't know" was then unacceptable. Now, of course, "Don't know" or a similar form of words is a frequently used part of any authority's vocabulary, and, conversely, one should be suspicious of anyone in this field who doesn't use it.
Hajdamach is quite interesting in this respect. He is positive about such terminology, but his references are rather difficult to find, the above being in a picture caption. The book is interesting as well for what he left out. His publishers obviously needed to sell the book in quantity to make a profit, so he took it quite gently, trying not to offend anyone.
I think future glass historians will come to view the book's publication in 1991 as the date when a new realism came into attributing British glass. This has been both helped and hindered by the Internet. Helped by making information and opinion more readily available and open to criticism, and hindered by the continued need for eBay and other sellers to use terms such as "Nailsea", as that is what many collectors search for.
On a lighter note, I actually saw the following attribution in a British auction catalogue some years ago â€” "Possibly European or American". What an elegant way of saying "Beat's me â€” I haven't a clue"!