Old Habits Die Hard
The typewriter on which I learned to type, at a tender young age before personal computers were really a thing, was the same one on which my mother had learned. It had no number '1', and may have not had a '0' either. You were expected to use 'l', which, being Roman type, had little serifs on it like a '1'.
I believe this was not uncommon in the age of the electric typewriter, and the vicar in this story had probably learned the same way.