On the MY23 Plus Six the Bluetooth module and USB have different fuses. I think the power supply to the Bluetooth was either dislodged or removed and not put back when the dash was removed by MMC to check the earthing behind. They were chasing a "Drivetrain" fault which they thought could be either fuel supply or earthing, and starting at the back were working their way forwards.
Good news is the Drivetrain fault seems to be solved, but frustrating that in doing so another, albeit less serious, issue has been created
