I've never heard it being used on an actual advert, but it was certainly used on the trailer on Channel 4 for T4's outdoor concert in Weston-super-Mare recently.
Thanks very much. Thought I'd heard it before somewhere and was trying to convince everyone in the office who thought I'd gone mad that it was on an advert. gonna have to eat humble pie now but at least you've solved the puzzle. Cheers, Cxx