I'm having this issue too. It started about a week ago. I finally got through to someone at Sky today, who ran checks and said everything was fine. I asked why it kept dropping out, if that's the case. He said that I am guaranteed speeds in a range of 0 to (maybe) 10, so therefore they were fulfilling their end of the deal (by providing 0, presumably). I suppose that makes a strange sort of sense, in a parallel universe. He said I would have to call back when it happened again, because he could only order an engineer when it was actually not working, or he would get into trouble with his boss. But, like you, it comes back on before going off again later. I'm considering changing to BT, although their "broadband with no landline" product includes a £5 charge for...phone calls.
