Thanks for this - I just transferred dollars to my US account about 2 weeks ago, ready to pay for Disney World tickets for next month... which is now not happening... so I took advantage of the drop and changed them back again:
I exchanged £450 initially (rate of 1.31), which came to $590... and I just changed $550 of it back into GBP and got £467
. If I had changed back all $590 of it, I would have got £503, but I needed to keep some of it in my US account.