Is there any alternative to the Marshall Bluetooth App for the Acton / Stanmore II / Woburn Series?

Specifically is there another way to link up two speakers to a stereo pair? Maybe a desktop client or maybe even a command line tool?
Or is anyone aware of an e.g. an open source project that reverse engineered the protocol? I can't be the only one out there finding the app horribly unintuitive and poorly programmed, also some functions simply do not work - e.g. source selection for a coupled pair.

Thx...

I want to change the source for playback (from samsun sound picker to google play).  Initially i had these two choices but now unable to access them.