IIRC Carl Lindström produced the first double sided discs in Europe, I believe on Odeon and soon after that on Beka. European Zonophone (which as far as I know was already a separate company from American Zon-o-phone) followed in the same year. G&T, who always were a bit snooty, kept issuing single sided records until well after 1910. European Columbia started producing double sided records around 1905/6.
Even though the U.S. and European Victor/G&T and Columbia companies were closely linked, there was a great deal of freedom on both sides of the Atlantic. They did use each other's matrices, but that was about all.
Operatic music stayed single sided for a while, but discs with popular music were mostly double sided from 1905.
European label history is patchy, to say it mildly. So many archives were lost during WW1 and in particular WW2, that it is impossible to make an accurate reconstruction. The great late Harry van Oirschot tried to compile a concise European label history, but shortly before he passed away he confessed to me that is was a Sisiphus labour. One step forward resulted in two steps back. That in particular was the case with the Lindström labels. With those there is more confusion than clarity. There was no clear matrix number structure and any recording - even different takes from the same session - could be issued on as many as 6 different labels. It was a challenge that made the crossword puzzle in The Times a doddle.
Anyone interested in the early history of British record labels should visit http://www.normanfield.com.
Norman is compiling an illustrated history which should eventually include every British label issued during the period 1898 to 1923, drawing on the extensive research of Frank Andrews.
Many of these labels were attached to European pressings, imports of which ceased abruptly on the outbreak of the First World War. As a result, many of the small companies which relied on these imports were forced out of business.