The 'blind' window is where the wardrobes are - no seats there. Also just about visible in that picture is the 'area ruling' of the rear fuselage where the fin starts - the fuselage is noticeably 'waisted' there.
Glad you enjoyed the event at 204, Dude. I have a lovely painting on my wall of G-BOAC on the roll-out on her last ever landing at EGCC 31st October 2003. It was signed all around the border by all the Concorde crews present that evening that I could cajole into signing, then I got it framed!