Sky has hit back at Discovery Communications after the American channel last week threatened to pull its channels from the European pay-TV giant over a carriage dispute. Sky says that Discovery was demanding to be paid close to £1B ($1.25B) for their portfolio of channels, including TLC and Eurosport, a price the company wasn't willing to pay to the $12B American company. "We now feel it's time to set the record straight," said a Sky spokesperson. "Because despite our…