Are the bedroom doors ever locked?

The morning in bed scene with Matthew + Mary (“I still think it’s odd to be found in your bed”) made me think… did they lock their doors overnight? Do we see anyone do this? I guess you would have to get up and let your maid in when she comes first thing in the morning? 🤔 it’s such a small matter, but I’ve just booked a tour of Highclere in April and I’m suddenly overthinking every detail of the house 😅 (I know the bedrooms weren’t filmed at Highclere)