I've had the same problem .
Yesterday i phoned sky customer services , who did a test and confirmed that it had been dropping out several times over the day . ( it had been dropping out since saturday )
Lady asked me to try connecting a different thingy that the sky box plugs into , from the bt line - but it didn't work .
She said she will escalate it for an engineer to do further tests and someone will call me in a day or two