Venu 3s low voice volume when watch and phone volume on max

I have problems with my Venu 3s speaker volume. Alarm volumes seem OK but volume for voice assistant or phone calls is barely audible. The media volume on my phone is max and the volume on the watch is max. 

Under Bluetooth settings on the phone  I set Audio Device Type to Speaker but is keeps reverting to Unknown Device Type.

I have completely gone through the process of re-pairing the watch and the phone which is hideously unworkable. It takes about half an hour of restarting each device repeatedly and going through the process in Connect to finally come up with a message like "Device cannot be paired" or similar. Eventually it will pair.

Anyway I have gone through this process 3 times and restored factory settings and it hasn't fixed it.

Also after first showing as connected in the phone Bluetooth settings it will show "Problem connecting. Turn device off and back on." Which of course I have done, to no avail.

And despite showing "Problem Connecting" it still syncs OK