Question

Why is Winsor outraged when De Levis says he had locked his door? What was the height of the room from the ground? How do they know that the thief did not use a ladder to climb up to De Levis' room?

Answer 1

According to Winsor, his house was a decent one and no one was supposed to be a thief there. And so there was no need to lock the door.
The height of the room from the ground was twenty-three feet.
Ladders were not used because there was only one ladder within three hundred yards and that was kept in the stables. Also, it was very heavy. When Canynge instructed him, Treisure went and inspected the ladder in the stable and found it was untouched.