From being lead pack in every triathlon and an ex- National butterfly / freestyle swimmer, its safe to say you're in good hands!
A Swimming only training plan can encorporate both pool based and open water based sessions. Added to this some (optional, but essential), gym / strength & conditioning sessions on dry land.
Drill work will feature heavily in order to help with the improvement of effiviency and therefore energy saving to shave those seconds off.
Weekly updated plans with feedback to track progress via Training Peaks. Access to coach 24h on Whatsapp.