Practically none. PS4 production has all but stopped and is completely out of stock in the UK. Xbox One too.
Amazon UK - No PS4 or XBO stock.
Game.co.uk - No PS4 or XBO stock. (They have preowned xbox one s)
Shopto.net - No PS4 or XBO stock.
PlayStation.com - No PS4 Stock.
TheGameCollection.net - No PS4 or XBO Stock
Smyths - No PS4 or XBO Stock
Very.co.uk - No PS4 or XBO Stock.
They are literally impossible to buy in the UK. They have the potential for more sales but production of these consoles has essentially stopped, everything is going towards PS5/XS.
This might be the first time that demand for last-gen consoles is higher than supply.