FindMyPast seems to have some less useful features as well. I have just been looking at the timeline for one of my ancestors and it says he was married on 12 March 1799, beside it is a link to click for the marriage record. Which I did, and it came up with no results. When I looked more closely at the search form, it had kindly autofilled for me, the Civil Marriage and Divorce box was ticked, not the Parish Marriages. So no wonder there were no results showing for a pre-July 1837 marriage.