Allroad Tyre Excessive Wear

I currently have Bridgestone S03 tyres on the car and this is my second set four of tyres in 15K!.
What is the allorad doing to my tyres. I have had the car wheel aligned nearly every 3-6 months over the 2 year period. I now at a dead loss as to how this can be cured. The alignment was carried out in the tyre shops at different shops.

Are Bridgetone S03 (225x55x17) the right tyre? some type fitter stay 6-8K is the max for this on Irish Roads. I have just tried the new P7 tyre and this is too ealry to tell.
Is there a special whell alignement that can only be done at the Audi Dealer
Is there problems with the Air Suspension?
I spoke to serveral dealers in Dublin and they see no problems with Allroad tyre wear on other cars.
What pressure works for the tyre 28 to 32 PSI?


Note: the tyres in the back are wearing in the outside and feathering the tyres badly.

Any suggestion would be great as a set cost 900 Euros and this is no fun for the cost of ownership.