there are NO Manx BMD certificates pre 1877/1880 - if you apply to General Registry (look up via www.gov.im ) then you will pay some £6 or so for a certified copy of the the official transcript of the parish registers - as this official transcript is available on mormon microfilm (see www.manxnotebook.com/famhist/genealgy/ldsfilms.htm) you can easily do it yourself