I started as a trainee broadcast engineer in London on £17,800 a year in 2003. This left me with £1,082 a month (back then student loan payments were far higher than now). Rent for a tiny bedsit with a shared bathroom was £520 a month, 2 mile walk from work. I could live further out, but commuting costs outweighed any savings.
That's the equivalent of £828 a month now. Bills were included.
You can actually pick up a studio flat for £737 in the same area, which actually looks better - it's about 60 square feet which I think it a little smaller than the one I had, but it has it's own toilet. Council tax is on top of that at £45 a month, but still fits in the budget, just.
Assuming the same 50% of take home wage in rent, or a net wage of £1500pcm, would be about £21k/year
My £17800 salary in 2003 would be £28,300 today, or net of £1900pcm, so could afford (on the same ratio) £910 a month, which gives you a fair amount of choice at the moment in W14 according to rightmove.
I'm surprised as I felt renting was far harder now than 20 years ago, but seems it might be slightly better. Of course rents on tiny studios are presumably depressed because of covid19, I'm not sure what they were this time last year.