This summer schedule IIRC it was just the few routes that usually use the 4 class 777s fitted with old CW seats, though they were in maintenance for a lot of the time! But seems like some A350 flights have also moved across now too (which was planned to be earlier, I was on an August LAS that was switched from T3 to T5)

Be prepared for annoying little delays - I've done 2 x Bermuda and 1 x Prague and all were delayed by either crew or aircraft coming across from T5.