When measuring the angle of the wall with the set-square (triangle ruler) the second measurement is clearly taken with a different ruler that is not a 90° right angle.
When Susanna goes to have a bath and she sets her phone on the night stand, she sets it down tilted toward the bed. Before Theo picks up the phone, it is tilted away from the bed.
On the website where they book their holiday home in Wales, the site misspells the word Sanctuary, spelling it 'Sancturary' with 2 'R's instead of just 1.