I doubt that an exact cause of this will ever be found, I also do not think that the water companies should be as vilified as they are being. They have a massive network of pipes & water supplies, some of it extremely ancient and IMO they cannot inspect and maintain it all constantly -there has to be some allowance for equipment & pipes etc to just age.
They do run regular tests and in their tests they picked this up, it took a few days to confirm what it was with extra checking and then to formulate a response, and then time to put it into motion - UV filters do not just sit on the shelves waiting to be bought - they need to be made to order.
Yes, there will be many jumping on the compo wagon, there always is - some people are going way over the top with shouting about the whole thing.
Just boil ya water or go boil ya head
