When I had a contract in Hemel Hempstead, I rented a double room, with sole use of family bathroom, sharing the kitchen and lounge with the owner. for £550 a month. This was the MOST expensive I could find, because it was the nicest, and NOT a HMO sharing with 7 x 22 year old party animals. Typically they were £400 to £450. The queue of people getting the train into london was Massive.
At the same time my son was renting a flat with another student in Mill Hill. £1300 plus bills. There were 2 double rooms, one with ensuite, and a big bathroom, a lounge dining room, and a tiny kitchen. I suggested he could rent the lounge out for £800 a month, but they preferred having a lounge.
I worked with a guy who was a Mech Eng Student at City University, in the 80's and in his final year he and 11 other Mech Eng students rented a pent-house with 3 bed rooms, in Chelsea, and put bunk beds in. Just so they could live in that area. Said if you divide the rent on a £2400 a month (in the 80's) by 12, it's only £50 a week each. which makes the £25 a week in the arse end of Coventry that I paid in the 80's for a 12 foot by 5.5 foot room, look a bargain.