But, post-graduates in London (if they have no other source of support) do tend to have a difficult lifestyle. Not recommended.
You don't get paid for being knighted. And these universities have a mostly fixed pay scale it's not like Google where you can just demand whatever you want if you're good enough.
Then again, there exist Business Schools, where due to the different funding model (most income comes from MBAs, as opposed to research grant overheads, and undergraduate tuition fees), full professors can easily make near-£200k in base salary.
[Updated to note: Imperial College quotes a fixed minimum salary of £79,080 for professors in 2019 with performance-related increases - so the Glassdoor figures quoting lower than that cannot be right]
The home.co.uk site quotes the median price of property listings is £600k (is that close to £1m? ok sure). It also identifies that houses priced higher than that are listed for significantly longer, i.e. they count with more weight in this stat despite not selling. Therefore, I understand the median sale price to be lower.
You have a lot to learn about the London housing market and UK salaries.