Hi @ChrisDoyle & welcome 
You can transfer up to £10K per day in up to 3 different ways - Bank Transfer, Card payment and Monzo-to-Monzo account and also up to £400 ATM withdrawals. So if the recipient had a Monzo account and could also accept card payments and part-payment by cash, you could, in theory*, pay a total of £30,400K in one day, split across 3 payments of £10K (bank transfer, card and 
-to-) and an ATM withdrawal of £400 cash to hand over.
*I’ve never tried it to the max, so can’t confirm 100% that it is doable. I have done a payment of £20K in one day though, using bank transfer and card payment - that worked OK
Joint Account limits:
