Manx Genealogy

John Stevenson & Ellinor Kewley m c 1745

I have this couple and only 2 children. John 1746 and Rebeccah 1749 baptised Braddan. I have searched high and low and cannot find a marriage for them. I have tried family search and cannot find them in Braddan (read all the films from that time) The nearest I have is on the members area of FHS for a John Steen and Ellinor Kewley on 17 July 1743 at Marown I have tried to find the film on family search to see if it was mistranscribed, sadly no luck . Can only find 1778 onwards. Help please. (Also any other children.)