Yeh I know but how do you diagnose it by just looking at a. Wall? The problem arose in the 70's when rising damp and replacement wall ties we're invented. All that drilling would loosen the snots and I would say wall insulation caused it also. At the end of the day he has been ripped off with work that didn't need doing and it looks like more problems have been caused, as usual human error.we use to clean out loads of cavitys back in the day