Hi Peter:
Thank you for your private message. I though I'd address your question about the manufacturer in this string, in case anyone could interject an opinion.
During the teens and 1920s, when the key patents held by the major phonograph/gramophone manufactures--The Victor Talking Machine Co./The Gramophone Co.; Edison; Columbia--began to expire, hundreds of companies started to offer competing products in order to tap into this lucrative market. During the 1916 to 1923 period, over 263 companies sold talking machines in the United States, alone.
Several years ago, R.J. Wakeman wrote an excellent article about this, which is available online --
http://www.gracyk.com/makers.shtml
As Mr. Wakeman notes, many of these firms were well-established prior to the time they sold talking machines. In fact, it wasn't unusual for a company, known for manufacturing pianos, organs, or other musical instruments, to offer it's own version of the Victrola or Gramophone, such as the J.P. Seeburg Piano Co. or the Starr Piano Co. of Richmond, Indiana, which is even more famous for the Gennett (brand) records it manufactured.
I have been told that a similar situation existed in the UK and throughout Europe, though, perhaps, to a more limited extent.
Since most of these companies were only in operation for a few years, I suspect that Bluthner's venture into talking machines may have been short lived. But, while there is nothing about the gramophones it manufactured on its web site,
http://www.bluthner.co.uk/about/history.html (Main Page --
http://www.bluthner-piano.co.uk/) it may be worth your while to send them an email and ask if they maintain an historical archive or library. You never know; they may have some copies of old advertisements, or other literature, they'd be willing to share with you.
