I suspect (pardon the pun) foul play. Plastic drainage as a rule doesn’t “get damaged” . I had a few issues with one gang of Brickies so maybe that’s the cause. Anyhow as we’re a reputable builder there’s no faffing with the Nhbc, I’m up there Thursday to remedy it. Thankfully stoner its block beam floor with a miserly 75mm screed on it.
[cant find sigh of relief smiley face]