As part of the Terms & Conditions (Section 20) which you have accepted upon starting your application, you must update your details if they are not current. This includes your residential address, a change of name, contact details, a change employer or you discover that the information you gave in your application was incorrect in any way.
You can update your mobile, email and address details any time by logging into your account. Click on the appropriate 'Edit' link in your Profile page to update the details.
To update other details (eg a change of employer), click on 'Personal details & inductions' link on the side menu.