Some did use to go for both tbf - Muse did both Glastonbury and Wembley in 2010, while Foo Fighters were meant to be doing both in 2015 before Dave Grohl's Swedish stage stumble. I'm not sure if LP were on Glastonbury's radar necessarily though.
Working out where they might turn up in the UK is a tricky one. Isle of Wight and Download were possibilities but both are now spoken for, BST Hyde Park is running out of dates, they don't seem to be in the Glastonbury chat, so could be a guessing game.
Tbf this festival does book stadium level acts now. So it's not a no imo.
I definitely need to know how many cash registers Coachella has. It’s the best indicator of how the festival has it’s fingers on the pulse of the music scene
They seem to be a secondary ticket seller - so selling tickets they’ve bought from other people. I suspect a number of people with hospitality tickets do try to sell them on, but I think if you buy them it probably does come with some risk as they’ve not been supplied to the company by Glastonbury itself (as far as I know). Can you find reviews of them maybe?