I would be cautious about assuming you've "bought out" the clawback when in fact there is nothing for you to buy out. This may be the way that SDCC are interpreting it but it's not necessarily something that would stand up in court, in terms of the way that the legislation and your contract were drafted.
As of last year DCC were officially taking the position that the no-renting rule still applied in such cases. They're now, apparently, turning a blind eye but this is not the same as saying that there is no such rule. So it seems to be a matter of local authority policy. You should get confirmation from SDCC before proceeding, preferably in writing.
Incidentally, it wasn't just SDCC's interpretation that you had to pay the clawback when you remortgage - that's the way the law was written. The Housing Minister in the last Dáil promised to amend the law but it never happened.