I give meter readings each month, why is my bill still based on estimates?

Smart Meters submit the reading the day after i.e. the Meter Reading for the 1st February is submitted on the 2nd February to cover the entire day. OVO’s billing platform is designed to be Smart Meter First in this regard, so all meter readings are treated this way.

While you won’t see the “estimate” being removed retroactively (legally speaking it MUST stay this way) you can remove the issue by either getting a Smart Meter, or doing the reading on the day I suggested in the cycle. It’s worth noting that if an Actual Read wasn’t submitted for the day the cycle reset, then OVO cannot start the next cycle with an Actual Reading anyway.

Either way, the next time an Actual Reading goes in, your billing will update and recalculate everything up to that point using the Actual Reading, thus cancelling the estimates out. You won’t necessarily see this, but it will trigger.

This is a feature, not a bug.

That’s the way it has to be. One billing period must necessarily start with the previous period’s closing figure, however it was arrived at. This will happen each month when you don’t submit a reading on the first day of the billing period.

Can you see your meter readings in your online account? Or the billing details for the current period? I’ve had a smart meter for so long that I just can’t remember what life was like before ... 

Yes you can, it’s on ‘Meter readings’ at the right of the online account, and on the billing itself.

Below is a clip from my gas bill last year when I still had a dumb gas meter so had to send in gas readings.

​@Feel fed up 
My billing period is the 24th to 23rd of each month, as you can see below I sent a reading on the 24th of each month, (the first day of the billing period), and so there are no estimates on the amount billed.
This is for gas, but it works just the same with electricity, that is:
To avoid estimated billing you need to send a reading on the first day or a billing period and not the last day.

When you send in a reading it gets allocated to the midnight at the start of that day, in other words it is allocated to the full day before the reading sent.
So by sending in my readings on the 24th they were allocated to the end of the 23rd, which is the end of my billing period.
If I had sent my readings on the 23rd instead, then the would have been allocated to the 22nd, and there would be a 1-days estimate for the 23rd.