Updated on 25/09/23 by Abby_OVO
OK @Peewyn that is about as much that any of us can do on the forum in terms of diagnosis as we are just customers like you and can't obviously access your account.
I would put in a complaint so your issue is easy to track etc.
https://www.ovoenergy.com/feedback
Include a link to this thread as your screenshots will help.
https://forum.ovoenergy.com/my-account-140/usage-not-in-pounds-14278
Point out.
1. OVO are getting smart meter readings on the readings page
2. The tariff details are correct on the plan page
3. The bills are updating correctly on the billing page
4. On the app on iPhone/iPad on the Usage page the kWh data is displayed correctly but there are no toggle switches for. KWh/£ on the Month or Year tabs
5. On the website on the usage page the kWh data is correctly displayed, but a missing data message is displayed on the Monthly and Yearly tab when toggling to Cost.
6. It looks to me like an account specific issue as it impacts you on both the website and the app, albeit slightly differently.