Earlier quoted context omitted.
You can easily make £400+ a day with tech contracting in London, yep. I've been doing it for years and I'm defiantly middle of the road. If you're a niche expert (MUMPS, KDB, etc.), you can probably make double that.
May I ask what's MUMPS , KDB?
https://en.wikipedia.org/wiki/MUMPS
KDB is another bonkers database language popular with banks and high-frequency traders.
https://en.wikipedia.org/wiki/Kdb%2B
(There is a common theme here!)