Good stuff, the 60p thing is a Scotland issue, it’s got high local distribution costs thanks to all those highland and island properties.
Just on the apps, the Ohme charger can’t overide the Nissan car, there isn’t any communication between the two. For example, if you get a schedule in the car to charge at 11, and the charger to start at 9, the car will not start charging until 11.
With IO you are seeding control of the charger to Octopus in return for better rates. When you do this, you have to set the car to charge whenever it’s given power (e.g. no schedule) and then Octopus handles the rest per how you tell it to charge in their app.
You can basically ignore the Ohme app unless it stops working. Use the Nissan app for everything else other than charging.
The octopus app is pretty good for monitoring g energy use from your smart meter. You can also ask for a ‘home mini’ which will give you real time use in their app.