Worth noting that (IME) US day rates are a lot higher for pentest work :) your US rates sound similar to what I've seen but Morrbo's UK rates sound ballpark right for the UK (I'd have said a little higher but it does depend on the company and work)
More bespoke services like proper red teaming, DDoS simulation IOT/connected cars/hardware were about double that.
£800 a day is the very bottom of the price scale in the UK for general SME public sector companies.
£800/day is low, but not unheard of especially if you use freelancers/small boutiques, but £2k/days is more than I've seen for most things in the UK.
We didn’t really deal with retail banks the banking clients would be investment and asset management banks like RaboBank.
When I was working in financial firms, there were internal red teams running vulnerability scanners or manual pentest (manual requires much more planning and coordination) . No point in paying external firms £10k per app to run an automated test. I am gonna have to consider changing side if audit firms are really billing £2-4k a day for this.