In order to change any of your personal information, such as  address, you must first log in using your user name and password, then click on your user symbol.
The user symbol will show the full account information.
Then click on "Account" in the left hand menu.
Then in the "Personal Details" tab, your latest address information will be displayed.
To change address, enter new details and Save
See link : https://www.admiralcasino.co.uk/en/user/personal-settings/personal