It will not fly to LHR as they would/could not make the necessary changes to stands to handle it. MAN I believe said no problemo!
It wouldn't be a real problem at Heathrow. Scheduled Cargo flights are negligible now and there are no times when all three cargo stands 607-609 are all scheduled to be in use. Hence they could happily use 607 and 609 leaving 608 empty. It's also possible to use the 610s for smaller aircraft than the 747s.