Oubound CallerID

Hi I’m new to Free-PBX. I’ve setup a Free-PBX Box and a SIP trunk which is all working perfect. I had my existing office number ported over to the SIP trunk as DDI and I get that to display using the fromuser= command in the Peer Details of the trunk. Recently I purchased another DDI for my London office and setup the Inbound Route for this particular number to go to my London extensions. It all works fine, But I cannot get my London number to display as the outgoing caller id when my London office makes calls from there extensions. Do I have to purchase the CallerID module and make the callerid persisitant?? Any help would be greatly accepted.
Kind Regards

It would be much easier to help you if you provided a little more info about your system nd its’ configuration.

Have you configured the London extension to use the new number as the CLID? Making a route for inbound does not set the phone to use that inbound number as the outbound CLID.