I can't see the pic very well. The rack's not resting on the glass is it?
I got a Mont Blanc mated to Land Rover roof bars. It's never let me down but I still bungee up at all the contact points. At work they very kindly bought us a Corsa with the cycle carrier built into the rear bumper. Bits a marvellous device, just a Shame they never checked with us before spending their money cos 2 out of the 3 of us trainers don't fit behind the wheel...