Yes, hotels in all the UK are way more expensive than ever, specially on Saturdays, can't say if Brexit has something to do but next year I have three travels to the UK planned, all of them involve a Saturday and is insane that usually a room hotel that cost 60 pounds on Friday, double the price or even more on Saturday and then go back to the cheap price on Sunday.
I recommend to check places like Travelodge, Premier Inn and chains like that, they are usually the best prices between the craziness of prices, including the usually cheaper B&B.