They got up there very easily, they are sitting on the wall of the car park that was above BHS.  It was easily accessible via the west side of Churchill Square where there was a car ramp up to the car park. I believe that BT had offices above Churchill Square and the car park was used by their staff, and perhaps other Churchill Square staff.  In my opinion a great photo of the terrible architecture of the 1960s that never did justice to Winston!

Very easy access. My friends and I used to spend many evenings running the rooftops of Churchill Square in the mid 70s. BT (or the GPO as it was then) did have offices there. Later, in the early 80s, the office car parks were opened for public parking on Saturdays - how I remember sitting in a queue that spiralled up to the car park.

This is a real trip down memory lane!  I remember that BHS. My older brother worked on a Saturday in BHS and lent a friend of mine the money to buy a Bad Manners album (on vinyl). I also remember the exotic sounding (well, it was to me as a kid) Solarium Cafe.  I also remember getting stuck at the top of the down escalator that led to the dingy toilets. In my defence I was 5 years old and the sight of my mum disappearing down the escalator was a big shock!  I am over it now. I can still remember the smell of industrial strength Dettol, steaming up those stairs.  One more memory - getting stood up by a girl outside Bejams. Her loss, not mine.  No, sorry, one more: who remembers the wishing well?