Death certificates can be purchased from the registrar on the day of registration. They cost £11. It is likely that you will need certificates when it comes to sorting out the person’s affairs.
If you need to, you can also apply for a copy of a death certificate.
Correct a death registration
If you find that the death register entry contains information that was not correct at the time of the registration or relevant details have been left out, it may be possible for the details to be changed or added later.
An application should be made to the registration office where the death was registered. Advice will be given on what is required for the correction to be completed and how much it will cost.
It may be necessary for the Corrections and Re-Registration Section at the General Register Office to be contacted.
See GOV.UK: Correct a death registration for more information.