Bluetooth headphones

I am trying to get my sony bluetooth headphones to work with my vero+.
I have paired them on the osmc network page, or at least it says paired and the icon has turned blue, but there is no sound. I have gone to the system, audio page but there are only two audio output devices listed "default( aml-m8audio; hdmi, s/pdif & analogue) or aml-m8audio; hdmi. Neither works.
I read in another post to install sudo apt install a2dp-app-osmc but I get “unable to locate” error.
How can I get them to work?

Try this [How-to] set up Bluetooth audio

Some self-assembly required.