I had the exact opposite - there was a birth registration in the GRO Index that had no corresponding certificate. When queried the GRO came back with the explanation that there are rogue entries in their index and they can do nothing about it. Lucky contacting the Registry Office where the birth was thought to have been registered, and supplying them as much detail as we could resulted in the birth certificate but about 2 years earlier then we had thought, and all for the cost of the certificate, even through the Registry Office had to do the search. So I would say if no joy with the GRO contact the Registry Office and see if they can help. Kevin (England)