A word of caution to anyone using the ladders on the Northern side - the platform at the top of the second ladder is very rusty metal, and is best avoided - go ladder to ladder. One of our party was crossing it and their foot went through, resulting in a reasonable amount of metal falling on my head as I got to the top of the first ladder below. I was lucky as I was wearing a helmet (fancy dress for exiting at street level) so the damage was minimal, but wouldn't want anyone to go through. On the plus side there is now a child-size foothole in it, so you should be able to spot it.
edit: visual aid now attached.