I have a used Brodit 652106 car mount for the A8. If anyone is interested I will send it on for £10 including postage.
http://www.car-mounts.co.uk/proddeta...od=652106_1778
It will have four screw holes which would be covered up by whatever phone mount you use. I currently have one for the HTC Desire if that is what you need:
http://www.car-mounts.co.uk/brodit-p...htc-desire.asp