Tried to transfer 1000GBP (40kbht) to Thailand after reading the OP this morning ............ doesn't work. The confirm button is 'greyed' out.
(and the pink warning originally stated 28kGBP, now changed to 28kbht)
Tried again 500GBP (21kbht) .......... button works, no pink warning.
So looks like they're limiting their exposure to wild currency swings.
Like I said earlier, bet it'll be back to normal on Monday when they aren't risking the W/E '3 day' exposure.