I've previously used Kashflow to setup invoicing and automatic payment through GoCardless, but it has it's limitations.
When you setup the process through Kashflow, you have to stipulate how much the maximum direct debit available to take is. For our purposes, we normally do three times the expected monthly amount, but for amounts that maybe only £15-£20 per month, that's a low figure.
When chasing payments for other work, our clients would ask us to "take it from the Direct Debit" but as the overall monthly amount is low, we cannot.
If you setup a Direct Debit directly with GoCardless, then their standard payment scale of approx £5k takes affect. The clients doesn't get advised of this amount and doesn't get scared of that big figure.
But when we do additional work, we can offer to take payment from their existing direct debit and they are happy to have less stress of making the payment. A win win.
Unfortunately you cannot at the moment, raise an automatic invoice and then collect the payment through GoCardless in that matter.
Can a request be added that the ability to pull funds through and existing GoCardless agreement be made available when creating invoices in such the same way as is possible if the agreement is created from within Kashflow.