The Claerwen accident was due to a snatch pull ripping the tailplane off - 4 Hunters coming at you in the opposite direction tends to do that. Subsequently several flight trials were made to get a viscous damper accepted which would have made this harder to do but I don't think it got adopted.
XV345 pulled 5-6g earlier in the sortie but what got them appeared to be a really strong side gust as the aircraft was banked over in the turn so it is a little unfair to attribute it to the actual manoeuvre at the time. They were trying to evade some Aggressor F-5s that had got down to their level.
Most aircraft have rolling restrictions at high speed/g and the Buccaneer was no exception. It was noted that the low altitude weave technique had changed from unloading and then rolling to just rolling which didn't help the wing fatigue.