[The T.I.B.]

Have both wheel arch liners out straight away, you don't need to remove the wheels they are just held in by 5 push clips.

Clear the 4 inches of dirt that's collected and you'll see the end of the sunroof drain tube.

At the top, the sunroof drains through each of the 4 corners into pipes between the roof and the inside headlining (which can be removed) which in turn feed down the pillars