Thanks to Winston for the link, and to Lyn for the first photo, which I think could run and run until someone comes up with the answer. Those upstairs windows were very wide, and divided into three with two narrow bays either side. That should be unusual, I would think.
Oh, by the way, when we moved into our new 3-storey 'town house' (as the agents called them) in Croydon 40 years ago, we were lucky that the builders were still working nearby. Without asking, one of the builders saw our new settee arrive, sussed out the problem, took the first floor window out and got his mate on the dumper truck to lift it up. It sounds dreadfully mean, but I think I only gave them a quid each - this was when beer was about 1s 8d a time of course.
Peter