Today at Boots Birmingham High Street they had Mark Hill shampoos and conditioners for £1.00. I suspect the bottle design is being discontinued. After a battle at the checkout where the operator told me I couldn't use my £2 haircare voucher, I insisted she try, and yes you can! Two bottles for the price of the voucher!
I can't say if this is nationwide but there were all types of bottles. They were all gone in no time once the queue had witnessed me with the cashier!