That was interesting, so thanks for posting. I went to school there until I was 8 when we moved from Stradbroke to Walkley and then went to St Joseph's Walkley.
I had my picture taken as an innocent 7 yr old on First Holy Communion day, in front of the door in the 2009 picture.
That was the best I could think of but the B looks to be in a circle and there was usually an S for Sheffield. I think you have the most likely there though.