I think its the B pillar finisher he's referring to Stu.
I changed the ones on the 1.8T I used to have, not an easy job but had no trouble with nor caused any damage to the seals. Just take your time and do it on a hot day!
By the way Peter, if one side needs changing then the other will as well. They rust from the inside, by the time anything appears on the outside then the inside will be rotten. Mine had a few rust bubbles appearing on the outside but when I got them off discovered the inside of both was gone.