Oops, this got mixed up with the other note.

See the footway leading down to the left of the tower, it leads to an entrance in the curtain wall.

Again visible here; entrance has a gate inside it.
- https://www.mapillary.com/app/?pKey=924351995049768&focus=photo
- https://www.mapillary.com/app/?pKey=1108168626371047&focus=photo