Thanks for getting back to me so quickly and for the welcome!

The 3rd party data we're sending to QuickBooks does specify that the payment terms are Direct Debit but there doesn't appear to be an option (e.g. using Zapier) that will let us send an instruction to toggle on the 'Use Direct Debit' radio button that is for the GoCardless mandate. Unfortunately, if this button is not toggled on, even if there is a mandate for the customer, the payment for the invoice is not collected.

I've corresponded with GoCardless and they've said that QuickBooks would have to make this accessible to the partners they have integrations with (e.g. Zapier). Could this field be added to the 'Update invoice' action in Zapier?