They're high, especially for a chap who will likely play only fifteen to sixteen songs at an hour-and-a-half, but maybe this is the time where his shows can start creeping towards the two-hour mark. You never know your luck.
I'm all for picking a heritage option if one is available. I'm all for the festival not breaking their backs to ensure it at the risk of mitigation elsewhere.
Sam Fender and Fred again.. are two R+L bill-toppers - the proper toppers too, not in a co-headline cobblers sense. Not saying it is a definitive caveat - Post Malone, three years ago there, probably isn't one to consider - but it's not a bad yardstick.