Heathrow doesn't "close for the night", but very many congratulations to the intrepid fund raisers. There have been a number of similar events over the years. One air traffic controller rode his Pennyfarthing bike round Heathrow's perimeter to raise money and many, many thousands of pounds have been raised by ATC staff for the Guide Dogs for the Blind.
Keep up the good work, which will be greatly appreciated by many people..