Wanted advice on replacing open air roof

[noots1404]

I have a 1996 open air polo 1.6 cl and I am having problems with the roof (one side is going back but the other is sticking). I was hoping someone could point me in the right direction re a specialist to look at roof and have it replaced if necessary. I have tried a couple of local garages and they have not been much use. and I am having real problems in trying to find the necessary expertise. Any help you can give would be much appreciated. I live in the Greater London area.