The easiest way to get an exactly accurate bill is to get a smart meter and have it submit readings at least once a day (mine sends readings every half hour). 
OVO’s billing system updates every day to show you a running total of what your balance looks like. If there are no actual meter readings for each day it will base that balance on an estimate, using your last meter reading and other known factors eg your usual pattern of use. 
To get a more accurate bill just submit more frequent meter readings. 

Thanks but no until they resolve all the problems with them as well allow it to contact my PC/Laptop at home for me to be able to check the readings at any time I will have no trust in them.

There are various updates they do @sugarboat after the end of the billing day. Especially on the gas as there are figures from National Grid used to calculate calorific value but these are only published after each day. 

There’s a difference between your bill and what you see online, because that shows the balance on your account. A bill is issued once a month (for most users) giving the account balance at the end of the billing period. The account balance changes each day to reflect the cost of the energy you’ve consumed since the last bill was issued. So, it will normally increase from day to day, but it will of course go down when you make a payment.
  

• … until they resolve all the problems with psmart meters] as well allow it to contact my PC/Laptop at home for me to be able to check the readings at any time I will have no trust in them.

Any complex system involving electronic equipment and communication will run into problems occasionally, but they’re usually not insurmountable. My smart meter was installed in early 2017 and it has performed flawlessly ever since. 

I can check my usage and the meter readings in real time (more or less) using the In-Home Display thoughtfully provided by OVO when the meter was installed. If I want a bit more detail, I can call up this on my computer:
  

These data are half an hour old. What more could you ask for?

If you’re happy to wait 24 hours, the same data are available on the OVO website in excruciating detail, going back years. And the balance on your account will be updated accurately every day.

What is it that you don’t trust?

I have also had a smart meter for years. It hasn’t ever gone wrong or been put into payg mode behind my back. It hasn’t fried my brain (as far as I am aware). It’s the most reliable piece of equipment in the house. I look at the In Home Display when I pass it in the hall and can see if somethings racking up the electricity, eg did someone leave the iron on ? Not me obv.  I can see that my heat pump is ticking over as it should, or that the car’s started charging.

Knowledge is power!

All that and I know that my bills will be correct. No more getting down on my knees with a torch to read the meter.

Thank you.