Income levels wise, Numbeo is just a mish-mash full of noise and can't be taken seriously to judge salaries of skilled professionals(that's what we're talking about right?)
Sure, poor people have it better in Vienna because it's cheaper and has better social services than London but skilled professionals(developers and engineers) have it worse as underpaying is rampant in the tech industry there.
Sources: me living there and my friends living in the UK
Since parent comment was deleted here is my answer anyway:
I would say from personal experience, contractor earning 600 quid/day in London is more of an outlier than the norm, unless he is more like Principle level and working for FAANG type companies.
Your answer answers a question similar to mine but not quite what I was asking.
You take people A and B, person A lives in London, rents studio in the city centre, works as mid level engineer in a regular bank. Person B lives in Austria, rents studio in the city centre, works as mid level engineer in a regular banks. Who will have more money left after bills, food, taxes etc? Numbeo suggests that what you said is incorrect, as I pointed above but you might absolutely be right as well.
"Compare that to the likes of Monzo and Austria is at least 15 years behind." Many Monzo features(for example instant notifications when card is used) are not present in many, if not majority of UK banks.
Sure, poor people have it better in Vienna because it's cheaper and has better social services than London but skilled professionals(developers and engineers) have it worse as underpaying is rampant in the tech industry there.
Sources: me living there and my friends living in the UK