Dogs were the danger, but apparently Mrs.Rider did not keep dogs, and his progress was unchallenged.
He saw no light either in the upper or lower windows until he got to the back.

Here was a pillared-porch, above which had been built what appeared to be a conservatory.

Beneath the porch was a door and a barred window, but it was from the conservatory above that a faint light emanated.

He looked round for a ladder without success.

But the portico presented no more difficulties than the wall had done.