Any funds you add to your account(s) with us, including our Personal Pension, are taken from your linked bank account, so you’ll need a UK current account linked in order to make payments.
Setting this up doesn’t mean you have to commit to making recurring payments though - you’re more than welcome to deposit funds through one-off payments if you’d prefer!
You can also deposit into your Pension via an instant bank transfer, which can be accessed in Accounts > Pension > Add money, and you do not need an active Direct Debit for this. So, if you’d prefer to solely deposit via instant transfers then you would be more than welcome to cancel your Direct Debit mandate at a later date.