Leaking soft top/Adjustment needed

Hi all. After a time away from owning a VAG car, I've now bought a 2002 Audi TT 8n Roadster. Overall, it is really good, but I have found a leak from the convertible roof. The roof doesn't line up at the rear left hand side when the roof is up, therefore it doesn't seal against the rubber strip. The right hand side seems perfectly fine and seals well. The front also lines up correctly where the roof meets the windscreen. The 'skirt' is starting to go, but before I tackle that I wanted to fix the seal issue. All the seals are in good order, its just the roof appears to not be being pulled up enough on the left hand side. Anyone got any idea how to adjust the roof?

Just for anyone who happens to be searching for the solution, it turned out to be the lowest tension frame being stuck on the nearside. I took the roof off and straightened up the bar and added a washer too prevent the bolt twisting. I then put it all back together and it now lines up perfectly. I also found that the skirt had become detached so after a liberal coating of contact adhesive and some duct tape on the underside to supplement it, that too is now in good working order.