At speed there is a high pitched whistle. This is because the roof is slightly slack. Last time it took the dealer seconds to deal with the problem but they are 20 miles away.

Does anyone know how to tighten things up again? Is it a simple job?

I don't have a 500c but i had the same problem with my previous car (New Beetle convertible). I don't know if the 500c roof is that complicated as the beetle in order to do it on your own. What sounds strange to me is the fact that it was repaired and it happened again, normally it shouldnt.
The vw dealer fixed the problem and i didn't hear this sound again.

Hi

Did you get the problem sorted? It has just started to happen to mine if I drive over 20 mph.Its slowly driving me mad. Any tips? Thanks