Shangri-La have just posted that they've booked Henge on Facebook.
Tom Walker has confirmed that he will be there, as he's bought his own ticket. Good on him. That surely makes it a safe bet that he's going to get a slot somewhere too.
http://www.irishnews.com/magazine/entertainment/2019/02/14/news/tom-walker-i-ve-bought-my-own-glastonbury-ticket-again-1552245/