So I have read through the thread and here is what I would add to all of this.
1) I agree that "End of the day" is a non existent "decor", and likely a term popularized by people that did not understand glass and how it is produced. Their knowledge lacked the understanding of rolling a gather in colored shards to create a desired decor. Hence, "End of day for all of those pieces of broken glass and remnants at close of business. Nice concept, completely wrong, and has "stuck" to the degree it will likely never ever disappear.... Kinda like Tango glass and Michael Powolny.... an insurmountable internet myth....
2) "Spatter glass", to me is simply another term for "end of the Day" and simply is a descriptive term applied to a decor containing a variety of colors with no apparent pattern to their application.... in other words, they look like paint that was "spattered" on. Likely a second term that has nothing to do with glass production, and everything to do with describing something to sell it.... at least originally...... now it seems to be a commonly applied term to all kinds of multi-colored decors. This term and "End of the day" seem pretty randomly interchangeable depending on who is doing the description. "Spatter" type decors were made in a huge variety of countries.
3) "Cottage glass": This appears to be a term applied to what at the time was believed to be Stourbridge production. As far as I can tell the term really first became popularized in the late 1990's with a series of articles in the "Glass Collectors Digest", a now defunct American bi-monthly publication. The term appears to have been applied by the Author John Franks to described production he believed to be "one off" production made at the end of the day by glass workers for family and friends. I would assume that this term would derive itself from the concept that this type of after hours production was a "cottage industry".
I am currently in contact with John Franks and he and I are discussing this glass and possible Bohemian origins for at least some of it.
It is my belief that at least a portion of what Franks described as Cottage glass was actually Bohemian glass, developed as a line of production tailored to British taste and imported heavily. I have identified a number of shapes in the Cottage Glass articles as being Welz production, and some of those shapes are also shown as Welz production in the photographic records of the 2012 Tango Exhibit which traveled in the Czech Republic.
This importation of Bohemian glass appears to have started as early as the 1880's and was done by at least one firm I have identified from US custom records. This type of glass is also found in large quantities in the UK, and found in very small quantities in the US market now. There is mention in an 1885 US Customs document of a firm by the name of Lazarus and Rosenfeld of London. It is stated in this Customs record that they not only imported glass to the US as the firm of Lazarus, Rosenfeld and Lehmann, but the firm based in London was also involved in the importation of Welz production to both the UK and also Australia.
So, to sum it up, IMHO, "Cottage Glass" is a term applied to production which in the 1990's was defined as being "one off" after hours Stourbridge production pieces produced by the workers, but is in large part glass that I now believe to have been produced by Franz Welz and imported to the UK by, at a minimum, the firm of Lazarus and Rosenfeld of London.
Hope this helps....
Craig