Trying to find a compatible Bluetooth music adapter for 2013

[King Mustard]

We are trying to find a cheap Bluetooth music adapter for a 2013 Q5 (UK).

The car software states: "BNav_EU_P0206_D1", which I believe points to it being a 'MMI 3G Basic' system.

I bought this dongle from Amazon: MASO AMI MDI MINI Bluetooth 4.0 USB Input Adapters Music Interface MP3 AUX Cable Adapter for Car, which I thought may work.

The instructions for the adapter state to press Media then switch the source to 'Aux mode (external input)'.  However, when Media then Source is selected in the car, there are only options for 'SD card', 'CDROM' and 'AMI' (which shows 'No device connected').

Have I simply bought the wrong adapter?

When I search for "Q5 Bluetooth music" on Amazon, there are many results.  Can anyone please help me narrow it down?