Whilst it’s not really on the main topic here it is interesting, and explains why you can’t simply choose to keep an old meter indefinitely.

tt didn't take that long to find and read them.
I won’t link them. they are easy enough to find if you want to.

The Electricity Act 1989 - Schedule 7 refers to meters that are charged against being 'appropriate'.
(ie. certified, ‘Type’ certification is allowed).

The Gas Act 1986 - Section 17 refers to gas meters that are charged against having to be 'Stamped'.
(ie. independently tested/examined and certified).

So the readings from a meter that is out of certification should not be charged against, meaning that any old meter should should be replaced before it’s certification expires.

The Electricity Act states that if a customer was to refuse to allow a replacement of an already ‘expired’ electricity meter then "... the supplier may refuse to give or may discontinue the supply."

The Gas Act goes further - it is a summary offence to supply gas through an ‘unstamped’ gas meter, attracting a fine not exceeding Level 3 on the Standard Scale (currently up to £1,000)
From my reading of the subsequent clauses then if it is the customer who is refusing/preventing the replacement of an ‘expired’ gas meter it would be the customer who is regarded as commiting that offence and so liable for the fine.

Hi @Jazz,

It seems that our forum volunteers have already given some good advice here.

Unfortunately, you would need to agree to have a smart meter fitted for our fixed tariffs.

You’d be able to find the terms and conditions here (specifically under the smart meter section):

https://www.ovoenergy.com/1-year-fixed-loyalty-terms/v2

https://www.ovoenergy.com/2-year-fixed-terms

Please let us know if you have any further questions.