Report by LBS states "manouevering speed" - ergo a lot below Vne...
There was no reference to unusual attitudes, turbulence or any other
factor. The LBA report implies that the wing failed while being flown in
the certified flight envelope.

One assumes they would not ground the fleet on grounds of not being
airworthy unless they were fairly sure there was some structural fault.

Question is whether it was a singular fault, damage to the specific
aircraft, or generic to the design.