Spade, when were married adults in Britain (or Europe for that matter) a majority?
During the days of serfdom, nobody cared if the serfs were married or not. The Church certainly didn’t, as long as the silver pennies kept coming to the Bishop.
A normal procedure would be the following.
Let us say the Lord of the Manor needs a crop of new babies, for future slave labour force. He would get together the men from his village, raid another village and kidnap the women form the village.
If they lived far from his village (say 40 or 50 miles away), they probably spoke a different dialect anyway, and probably wouldn’t understand the speech of his village. So the Priest or the Bishop would say a perfunctory service on all the couples and that would be that. In due course a new crop of babies (and the source of future serf labour) will be born.
All this concern about people getting married started after the industrial revolution. But traditionally, the Church did not really care if the unwashed masses were married or not. As Orwell said in the book 1984, ‘Animals and Proles are free’.