You’ll need some rubber feet and some brackets to attach it to the roof. Have a look on ebay for roof rack rubber feet… or something along those lines!
I found the other little plastic thing in my boot and I’ve got some brand new nuts and bolts too. Picked up these little things the other day in the local market, £1.50 for 4 They are rubber walking stick ends but will fit the roof rack like they were made for it!!
I know need to make something like this, unless someone has a pair of these I can buy/have
Thought you’d benefit from seeing photos of my roof rack. Its very similar to yours I have rubber feet with felt underneath to protect paitwork. These came with the roof rack but I think my dad managed to get some grey rubber feet from a show. Anyway check out the photos, I hope they help, any other questions I can help you with just ask.
PS I know pictures aren’t brilliant but parents have borrowed my digital camera so had to take them with 2mp camera phone.