Checking your balance on a SMETS2 Meter is exactly the same as with SMETS1 meters.
If you’ve got the standard set up, which means you top up at the shops, and have a separate top-up card for each meter, then your balance will show on your In-Home Display.
If you have PAYG+ and have access to an app to top up, then your credit balance will show on the app instead.
That’s it, as simple as that. You can find out loads more info on SMETS2 meters here.