You can buy a Bluetooth device that acts as a remote control to your phone volume on ebay.
John, yes I've seen those, thanks. But back to the MY23 Plus Four and Plus Six handbook, page 23:
"WARNING Please ensure whilst listening to music on the premium audio system via a connected Bluetooth® device i.e. mobile phone, that the connected device’s volume is always set to maximum volume."So although I could control the volume from a Bluetooth device, MMC are saying that I shouldn't (or baaaad things will happen ...)
