Xbox Series X UK restock confirmed after GAME and Currys release
As explained by Box, all Xbox Series X consoles are sold through a ballot system, meaning you have to add your email to a list of other potential buyers. This gives you a chance at being allocated a console, without the need to try and queue up online. A message on Box explains: “Box.co.uk have decided to run a ballot system for the new Xbox Series X while stock is in such constraint and demand is so high. "The ballot system allows customers to sign up with their email address and name in order to be in with a chance of being selected at random to purchase a console.
Source: express.co.uk