As I said 500gbp/day is not much. I see a lot of IT people earning this is Germany, especially in the Devops field. With something like that you would get an average qualified person hired in, say, Munich.

That is my impression as well. My rate is currently around 445gbp/day for backend development in Berlin and it is far from being at the high end (according to a yearly survey run by gulp.de). My total monthly expenses including rent, health insurance, etc. are below 2k gbp. I do pay higher taxes though.

What's the situation like there with having your own business vs as things are here with a uk ltd company, or do you work via an umbrella corp?

As far as I know, setting up a "UG" is easy enough. I'm registered as a freelancer ("Freiberufler") with the tax authorities. I guess that's like a sole proprietor? Upside is that I don't pay corporate tax (because there's no corporation). Downside is that I pay taxes on all my income instead of keeping most of it in the corporation.

TIL I basically work for free. But then again, I hardly do any work, so it seems to even out in the end.