The coroners service will be in contact with the relatives of the deceased if the death is reported to them. It may be the case that there will need to be a post-mortem examination in order to establish the cause of the death. It may also be the case that the coroner may hold an investigation into events leading up to the death, which may also require an inquest.
If an inquest is held the registration will not take place until the end of the inquest, but a certificate of death can be issued at the request of the family to allow the funeral to take place. When the inquest is finished there will be a certificate issued to the registrar that will allow them to register the death.