Your recollection is incorrect, Pontius. The 'g' limits were significantly higher and we often flew sustained 60° AoB turns at 300'.
The Vulcan was cleared for manoeuvres 'appropriate for a medium bomber'. Barrel rolls were neither common, nor were crews taught how to fly them.
When the Vulcan was displayed at Farnborough, it was carefully inspected before and after each flight - which involved a technician going inside the wing to check the leading edge structure.
Ill-disciplined RAF pilots' mishandling probably damaged VX770 before it crashed at Syerston as a result of structural failure when the aircraft was being flown inside the approved flight envelope.....
If XH558 was rolled in the manner alleged, the culprits deserve no sympathy.