Feedback on Charging Networks or Chargers

The Wagtail , Wincanton has Osprey chargers and I have used these b4 using the Osprey RFD card but using the OVO app I couldn't find away of stopping the charger the only option was to stop the charger with the method you started it. So on the app how do I stop the charger? I have used the app before on Osprey but have never encountered this, I kept looking at the app but couldn't see a stop charging feature.