The chick is now a week old and seems to be doing really well. It is too late for the last egg to hatch. (It is hidden behind the chick in this video)
Bella is doing virtually all the feeding and incubation using food caught by CR. Sometimes he briefly appears to deliver food to the tray, and at other times, Bella seems to collect it from the "larder" higher up the tower.
Bella is quite houseproud, and flies off with any prey remains after feeding the chick. She also removes some of the sticks that have fallen from the pigeon nest immediately above.