One word of warning though...

Don't put the roof down if it's really cold...

The rear screens on most of the cars are getting on a bit now and if the plastic gets to cold it is possible for them to split...

My mate has got an MGF and he now needs a new rear window because it split when he put the roof down when it was very cold and his is only 5 years old...

I think that un-zipping helps as they don't have to fold as much but it's still not really worth the risk...

Ady.