Hi Neil, how about these:
http://www.tsl-motorsport.co.uk/newsite/pr...=129&query=
http://www.247ppd.com/product~prodID~853276.htm
These companies may be able to help:
http://www.potn.co.uk/brake-discs_c2918_192.htm
http://www.prodrive.com/products_level2.html?id=33&p=12
http://www.porsche-spares.co.uk/cayenne.php
http://www.alcon.co.uk/frameset.asp
http://www.amdtechnik.com/