There was a DVD release in the United States (it was "region 0", but was still official) from Digiview Entertainment, but it contained only the first few episodes, some episodes were "mapped" to the wrong titles, and it ended up being the Starla version despite calling itself Princess Gwenevere. This same DVD was later "updated" to contain a couple more episodes. It has since gone out of print.
Actually, there were since then also various releases in the other countries (in their local languages), and as of 2010 the whole series in English (along with other BKN series) is now legally available for viewing for free at the website Kidlet.tv, but requires free registration. As of 2012 the show is also avalable on Netflix.
The Other Darrin: In the second season, Gwenevere was voiced by Jean Louisa Kelly.