Logitech gear shifter not working with g920 wheel

Can anyone help? I bought my son the Logitech g920 wheel and pedals, which work fine. We added the Logitech gear shifter, plugged it all in. Have rebooted, pressed 3 buttons on the wheel whilst unplugging the usb and reinserting, etc. It just doesn’t register that it’s plugged in. Have gone into difficulty settings (forza horizon 4 on Xbox x) and chosen ‘manual with clutch’ yet when configuring there’s no obvious option to use this as the gear shift method. The paddles work with the clutch, but not the gear stick. Any ideas please? Thanks