Legend may be fact after all . I remember in the art class on the top floor on the street side there was a section of the plasterboard that was removable . With care it was possible to climb into the roof space or wall space and walk along and emerge in the art school. Which I did once and came upon a life class and a fleeting glimpse of a nude . I was quick to find a way out and down some flights of stairs to the basement corridor leading back to the old school.
As for getting old its better than the alternative .
Mike, during my time at the School that corridor, in which the panel was removable, was known as 'the cardboard corridor'. There were many holes in the 'cardboard' but maybe someone had got wise to an earlier generation than mine peaking at the nudes because we never knew anything about such delights so close at hand!