The UK mostly pays developers a derisory salary.

Australia seems to pay roughly on a par with the US, or did when I lived there. But most of the UK is dreadful - software folks are paid poorly and treated like drones.

Unfortunately there are enough people that will take the bad salary, have mediocre performance and deliver mediocre software slowly, that a lot of British companies now expect to pay peanuts and get monkeys.

I've found the only way to replicate the money you can get elsewhere is to be a contractor. You can make about double your quoted figure outside London (my experience in the Hampshire/Wiltshire/Dorset region), or triple or more if you land something bank related in London. No idea what might be available in Edinburgh.