Laurie, I stand corrected. The fuel was certainly an issue as the aircraft routinely used all 8000 feet of runway at Butterworth.
I agree about the comment on the RSO
There was a follow up to that photo. A copy was displayed at SAC HQ in Omaha and what so impressed the Americans was the bomb load was exactly the same weight as a standard B52 load 51x750. They then asked Bomber Command for a similar shot photo of the Vulcan dropping 21.
This ws set up for a drop at Aberporth with inerts. The chase aircraft was in position and the aircraft approaching the drop point. At the right range the bomb doors opened and the bombs went - a moment later ground control came up "Stand-by for drop in 5, 4, 3, 2 ............."
No one had told the crew the rop instructions would come from the ground.
The whole thing was set up again and another drop was down with live HE on El Adem range.