This is not a continuous flight of steps.
From Beacon Rd. there is a ramp up about 60M before the first steps. There are then 48 short flights 3-4 steps at first, then in 5s. The flights are about 6M apart. Near the very end thre is another ramp of about 20M, Finally there are 4 well spaced steps.
Most of this is clearly visible on google maps.
Here:
https://earth.google.com/web/@51.37146836,0.54980541,57.40463307a,132.06297124d,35y,0h,0t,0r/data=CgRCAggBQgIIAEoNCP___________wEQAA

Originally for female inmates. Don't know if it has a name - didn't know anyone who was there.

Originally Cornwall House was about here

Originally Gloucester House was here - mirror image of Essex House

Central Hall
Chapel (top floor)

Inmates Workshops

Essex House

Norfolk House

Kent House

Dorset House