Here's an eBay link to some roof bars and a top box
http://cgi.ebay.co.uk/Genuine-Discovery-3-Lockable-Roof-Cross-Bars-CAP500020_W0QQitemZ150145683896QQihZ005QQcategoryZ31348QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
Land Rover Discovery 3 Roof Box and Bars on eBay Touring Travel, Car...