in the uk nowadays, every time you want to go to the toilet (even your own) you have to upload your ID. once you’ve done that, it’s pretty straightforward: they let you book in ahead of time, and it’s best to reserve a slot 3-4 days in advance, though if you have a toilet card (loocard saver or regular season card) its best to book at least a week in advance, because if there’s anything wrong with your ID/facial scan verification they need to escalate it to support which can take 5 working days