Bill, the last one shown is 'Sally B', a B-17G owned and operated by Sally Ellingboe, and based at Duxford, UK.
If my memory is correct, she was one of the aircraft used by the French Geographical Survey, and has been based in the UK since the mid 1970s. Originally, she was in bare metal, in 100 BG colours, and lacked all turrets.
The top turret and ball turret were provided for, and funded by, the 'Memphis Belle' movie back in 1990, to 'pose' as a B-17F, and with an agreement to also provide a chin turret and other equipment after filming was complete. She still carries the markings from the movie, with the 'Memphis Belle' nose art on the starboard side, and the 'Sally B' nose art on port side, and is now the only B-17 still flying in Europe, the last French one being grounded a year or two back.
Here's a (poor) pic taken at Cosford 10 days ago.