Grape vine under polycarbonate roofing + pruning
 

We are thinking of replacing our conservatory but the new one would
have a poltcarbonate sheeting roof. Will our grape vine still be OK
even though the roof will not be glass?
Also, any help regarding pruning would be very helpful...have read
several sites, but we still a little confused...it is about 6 yrs old
and not been properly pruned, which is why, we think, the yield is
down
Many Thanks
Nick