Ok, understood, you have to get your priorities right 
The post does open with this line though:
"Hi you can fix high volume problem or say echo by editing: /system/vendor/etc/mixer_paths_0.xml
I’ve used MTmanager app after rooted with magisk "
So I suspect he is aware that my problem exists
No rush, as I say, I don’t get too many phone calls anyway. My more immediate concern is why the network fails outside of my home.
I currently have a full signal marked “H” and am transferring data with WiFi switched off so the hardware clearly works! It’s very odd indeed.
Happy studying
J