While I appreciate that there's a need to filter candidates, surely it proves that there is either no shortage of experienced developers out there, or that companies would rather hire less experienced devs with more relevant experience? If the latter is true, then companies shouldn't moan about a shortage in talent when there is obviously demand for more senior roles.
If candidates could see the other applicant's CVs it would kick off an arms race.
Two years ago, I took a role in a tech stack I've never used before, and in less than a month I was productive in Node and Rails. I work with half a dozen developers that switched from one stack to another, and regularly do so to use the best tool for the job, and it's not as hard as some companies make it out to be.
IMO there are few, if any, tangible signs of a shortage locally.
There's a definite shortage outside of London, although few companies seem to want to up their salaries to attract experienced talent. One of the reasons I switched stack was because I would get recruiters emailing every day with new roles, but rarely anything that paid over £45k in Bristol.
In your experience, as a Londoner, is there a demand for experienced devs? I would've thought that big companies would always be looking for developers.
If you apply for a job, the experience you list should match the tech stack in the job spec. Don't list roles that aren't relevant (i.e. no .net if it's a Python role).
I helped hire a DS this week. Their CV was among 20 excellent candidates all in London with their latest role matching most of the tech stack we're looking for. All the candidates are in London. This is what you're competing against.