How does Sir Percival gain entrance to Old Welmingham in the novel, The Woman in White?

The keys to the church and the vestry are kept on the same ring by the caretaker, an old man who lives in a cottage nearby. Though the church is abandoned and in disrepair, the old caretaker does his best to maintain the church and the property. The old locks on the vestry need repair and tend to seize up. Sir Percival breaks into the caretaker's house and steals the keys so he can tear out the fraudulent page of the registry kept in the vestry.