We had broadly the same issue some while back and a builder pal ahd a through look and could not find anything. We put the problem down to perpetual and heavy rain coupled with gusty conditions which meant that the most inconspsicous holes, gaps or crevices were found by the rain being plattered...
Not certain at the inherent negativity here Mendo. Is it just gut feeling or do you a point to make anout his keeping ability or maybe the fact that he doesn't organise his defence in front of him?