To view all for the searching of calls within the search page caller display needs to be enabled on your phone system (please review why-are-all-my-outbound-calls-appearing-to-come-from-the-same-number- for more information on this), however once caller display is enabled on your phone system this will also be presented to any customers you are calling. This is not always desirable.
To hide or change the caller display please select the Admin tab and then Features configuration, state the number you wish to be presented within Global Clid Override and click save. In the example below the number that will be present for all outbound calls will be 02920555444.