> The cost of living in London eats up any salary benefit.

Does it actually though? Genuine question having grown up here. I live with my partner, our monthly outgoings living on the zone 1/2 border are ~£800 each for mortgage, bills, car insurance, etc. Last year I earned ~£90k before tax. I don't think I would have earned anything like that amount working in another part in the UK. Even if my cost of living was halved I'd only be saving around £5k a year.

I'm relatively young I suppose and I don't love everything about London, but I see lots of benefits to living here outside of the income, too. I can also be in the (proper) countryside in an hour or so drive at the weekends if I want a change of scenery.