I think it’d be cool to be able to link a flex payment to a particular pot. If you use pots to organise your money by spending category, this would give the ability to see when you’ve overstretched in one area compared to another, rather than having one monolithic flex balance.
As an example, if you have a Holiday pot, and you overspend on holiday from your flex account, this would make your Holiday balance -£300. This makes it easier to organise and plan your upcoming budget 