How to add bluetooth headset to sound settings for mic and speaker?

How do I get the bluetooth device listed for sound settings:

I actually used this just a few hours ago, worked fine.

nicholas@mordor:~$ 
nicholas@mordor:~$ sudo dmesg | grep -i bluetooth
[   32.835495] Bluetooth: Core ver 2.22
[   32.835522] Bluetooth: HCI device and connection manager initialized
[   32.835533] Bluetooth: HCI socket layer initialized
[   32.835535] Bluetooth: L2CAP socket layer initialized
[   32.835537] Bluetooth: SCO socket layer initialized
[   33.889463] Bluetooth: hci0: unexpected event for opcode 0x0000
[   63.982936] Bluetooth: BNEP (Ethernet Emulation) ver 1.3
[   63.982937] Bluetooth: BNEP filters: protocol multicast
[   63.982941] Bluetooth: BNEP socket layer initialized
[  347.302265] Bluetooth: RFCOMM TTY layer initialized
[  347.302270] Bluetooth: RFCOMM socket layer initialized
[  347.302275] Bluetooth: RFCOMM ver 1.11
[ 8845.170223] Bluetooth: hci0: SCO packet for unknown connection handle 65
[29911.455967] Bluetooth: hci0: SCO packet for unknown connection handle 67
[29911.455972] Bluetooth: hci0: SCO packet for unknown connection handle 67
[29911.455974] Bluetooth: hci0: SCO packet for unknown connection handle 67
[29911.455975] Bluetooth: hci0: SCO packet for unknown connection handle 67
nicholas@mordor:~$ 
nicholas@mordor:~$ bluetoothctl
Agent registered
[CHG] Controller 00:1A:7D:DA:71:15 Pairable: yes
[CHG] Device F4:B6:88:10:87:E4 Connected: yes
[PLT V5200 Series]# exit
nicholas@mordor:~$ 
nicholas@mordor:~$ hcitool scan
Scanning ...
    00:CB:51:56:F5:1F   
    5C:C1:D7:F6:06:83   n/a
    00:CB:51:56:F9:A3   
    00:CB:51:56:E6:B3   
nicholas@mordor:~$ 
nicholas@mordor:~$ bluemon
nicholas@mordor:~$ 

I can click "pair" or "unpair" all day long without any seeming effect.

Again, just a few hours ago it was working -- and the headphones were listed in the settings GUI.

the headphones are PLT v5200 and are paired, complete with the bleep-bloop sound indicating the connection.