It depends where the money landed, that's where the big fees would be made, but just shuffling it around, I'd be very surprised if it was more than that.

Look, you can bring up minuscule footnotes in Appendix F of what matters to the UK economy as much as you like. Yes these things suck. No they are not even remotely consequential to why a taxi driver in London, or Londoners in general earn what they do or how a modern economy functions.

The more time you spend obsessing over incidental edge cases, because they are things you can get enraged about and get a good adrenalin buzz over, the longer you will be mind blastingly uninformed about how the word really works.