I have a Thule Pacific 200 roof box for sale - £125. It has been used once to take the family to Scotland and once to Wales. No longer needed.
Info here -
http://www.towequipe.co.uk/products/roof-boxes-thule/631200-thule-pacific-200-luggage-roof-box-460ltr.html?utm_source=google&utm_medium=base&utm_campaign=products&gclid=CNf1nOjr6rECFYYNfAod2REATQ
I also have the roof rack with all the bits.