Disabling of A2DP not working since Lollipop upgrade

I have been a user of Soundabout Pro for some time now - I installed it under KitKat to force navigation commands to the phone speaker when connected to the car's BT and also to block media streaming to the BT connection. This worked very well up until I upgraded to Lollipop. Now with Lollipop, navigation commands from Google Maps app are routed to the phone's speaker when connected to BT by default (fantastic!) but the ability for Soundabout to disable A2DP for media streaming is now not functioning. I cannot disable media streaming in the phone's BT settings without losing phone call functionality. It seems to be the stock Android music player that kicks into life but this app cannot be disabled. I have all boxes deselected in Bluetooth Settings>Media Audio Behaviour.