I've remembered - I was originally paying by monthly direct debit before it changed to meters.
Anyway, reply received to my SAR:-
General Data Protection Regulation – Rights Request
We understand that you wish to exercise one of your rights under the General Data Protection Regulation legislation.
To comply with the requirements of the Regulation you will see that we have requested some identity information from you. This information is required by us to ensure that we verify the identity of the person making the request before responding and to ensure that we do not disclose any information to anyone, unlawfully.
On receipt of the identity documentation we will respond to you acknowledging receipt of the request and confirm when you can expect to receive a response from us.
We have also sent an information sheet which details what information is useful to give us as part of your request and details the data rights process at Centrica for your convenience.
For a most thorough search, it would be very useful to provide us with a full list of all properties where you have held products and services with us.
It would be helpful if you could specify if there is specific data that you are looking for; i.e. Hive data.
For us to provide your data via secure file transfer, security reasons require us to send your password separately. Please respond with the mobile phone number or postal address that you wish this to be sent to.
It would also be very helpful for us to understand from you the reason that you are making this request so that we can continue to look for ways to improve our company’s processes and make being a customer of ours a better experience.
We hope this clarifies our position and we look forward to hearing from you shortly.
Data Protection Manager
Centrica Privacy Operations