Thanks Nick, I think I'm as happy as I could possibly be with the siting and position. If I'm out on my own I still tend to use the top right hand corner of the screen with the suction mount as its right in the line of sight without blocking my view and I can hear the voice commands better but that's obviously with the roof down, roof up it's now to the dash mount!
Martin.
Someone in a related thread suggested Bluetooth earphones for following voice commands when driving topless. I have tried this and it works a treat. You can turn up the volume if needed when going flat out and no wires dangling from the phone.