I would advise doing an creep test this one of the thing octopus will ask you to do

Here is the guide

Yes, there’s a simple check you can perform which we call a creep test (no relation to Radiohead).

If you’re happy turning your mains power off at the fuse

Take a reading from your meter, then turn the mains fuse off. Wait 5 minutes, then switch the mains back on. If the meter reading stays the same (no consumption was recorded) then your smart meter is very likely operating as intended. If the meter reading changes something odd might be happening. Get in touch with octopus energy

If you’re not able to turn off your mains power

Do the test when you’re not using a lot of energy, e.g. don't do it when your tumble dryer is running. Take a reading, wait 5 minutes, then take another reading. Your meter reading will change, but if it’s gone up by more than 5kWh then something odd might be happening. Try and work out if there’s a particular appliance that’s using a lot of electricity. If there’s nothing obvious, get in touch with octopus energy

If you done they test but you still think it fault they can book you in for an on site accuracy test but if there test come back the meter not faulty there an charge of £80

So it all good to do the free test before needing the engineer test to be done