Good morning @Spangpan, and a warm welcome to the OVO Forum community 😁. It’s great to see our Superusers have been so helpful on this thread over the last few days - thanks all!
Just to confirm, the isolation switch needs to be installed by OVO, due to the supply being de-energised via the cut out, which is something that only our engineers can work on. We generally charge for installation of an isolation switch, however this job is free if it’s done during the installation of a smart meter.
@Spangpan when you book the smart meter installation, make sure to do it over the phone, rather than your online account, as the advisor you speak to will need to book this job in differently. The correct number to call is 0330 303 5063. Let us know how you get on!
Regarding your second question, you can absolutely pay on demand with a smart meter installed. You can find out more about smart meters and In Home Displays (IHDs) in our Forum library section here.