Guess you’ll just have to wait until the funds do arrive.
httpss://support.skybet.com/s/article/Mastercard-Withdrawals
Fast withdrawal option is usually 4 hours, but otherwise up to 2-5 working days if the receiving bank isn’t supported in fast withdrawals.
Taken from the Sky Bet page.
As they are within the 5 working day window (excludes weekends, regardless of how fast it’s been before), neither monzo or Sky will do anything until this window has lapsed.
At a guess, if it’s usually next day latest, close of play Monday would be a likely arrival time.