Hi Simon / Savan,
Yes, we did integrate using smart debit for direct debit recurring payments for one of our customers. They have API's for the different actions below;
1. Create direct debit instructions (DDI)
2. Cancel DDI
3. Update DDI
4. Validate DD details
5. For different reports such as DD collection (successful and failed), ADDAC, ARUDD, AUDDIS etc.
We faced some issues using smart debits as thier API's where not that mature but they where very supportive to update thier API's based on our feedback and helped to fix issues that we facedd. At the end we maanged to implement this successfully.
If you need more details then please feel free to give me a call or drop an email.