I am not sure that it is ...

I am not sure that it is beneficial to go for an SBR especially if there is a current or future phosphate and ammonia consent.  The aerobic stage of the SBR will remove these species but the settlement stage can reverse the phosphate removal.  When they go wrong extended time can be required for settlement and this is where issues can occur.  Unless there is good aeration and you have the correct carbonate level and the correct ammonia oxidising bacteria ammonia is not successfully removed.