Given that the register contains personal data, you should take measures to ensure that proper caution is exercised when sending this data to any of the entitled recipients.
While you should seek your own advice regarding the most appropriate and secure method of supplying the register to recipients, general security precautions should include as a minimum:
saving electronic copies of the register, either sent by email or saved to disk, in a password-protected or encrypted format with the relevant password or encryption key being sent in a separate communication
using secure delivery options provided by Royal Mail and other mail delivery service providers
maintaining records of what has been sent, the recipient’s details, and how it was sent
The Information Commissioner’s Office provides advice on encryption, available at https://ico.org.uk
Where you have used data encryption, you will need to ensure that any recipient can access the data.