Good question Amie
Motability do not give any details on the type of payments you can use, only it needs paying no later 21 days before your lease ends. I would try to use your credit card first, if not it wil probably be a bank transfer.
Do bare in mind you get no warranty or service as you would buying from a dealer so do take this into account
Hopefully someone with more knwledge on payment types, will be along later to help 🙂