A good searchable site http://www.northlincs.gov.uk/commun...yhistory/searchandorderbdmcertificatesonline/
The above link by Helen seem not to be working. I think they have upgraded their site. Try here http://www.northlincs.gov.uk/commun...ply-for-birth-marriage-or-death-certificates/
It is worth mentioning that the cost of a certificate from the above site is £10, as opposed to the GRO cost of £9.25. This is often the case when applying via the local record office.