I worked for a high street bank in the UK for many years in the 90's, we had "big city" allowances in our contracts, in effect, if you worked in London, you got an extra £3200, Manchester it was perhaps half of that etc etc. It was a competitive industry for staff so you had to pay to attract and retain. I'm surprised this never seems to have been applied here
As for "key worker", I think the issue here will be that in everyone's mind, they are a "key worker". We also are a nation of begrudgers, if the teachers get it, then the teaching assistants must get it, then the creche assistants and on from there.