Again, thanks so much. It seems the phone does BT 5, but the Shanling has 4.2.
As for the volume: it’s on again then off again. It’s baffling and frustrating, but right now seems okay.
I’ve just done a workout and the advice on getting a secure fit seems to have worked (although my workouts are far from vigorous) but tomorrow’s commute will be a true test. Everything’s become so erratic I’ve taken to travelling with two sets of wireless ear buds and a wired pair as back up!