I am trying to add TPN: Royal Mail Tracked 24 and TPS: Royal Mail Tracked 48 services but they are not available in the services drop-down menu of Royal Mail OBA integration.
Domestic Tracked services such as TPN: Royal Mail Tracked 24 and TPS: Royal Mail Tracked 48 have a different configuration to OBA services and are listed in a separate integration: Royal Mail Tracked. Once you add the Royal Mail Tracked integration, you will be able to find the TPN/TPS services in the Shipping Services tab.
Additionally this Tracked integration will include domestic tracked services such as Age Signature, Tracked High Volume, Letterboxable and Letterboxable High Volume. The full list can be viewed via the below link.
Once the service is added and you attempt to print the label for the first time, an automatic tracking range request will be submitted to Royal Mail and you should be able to use the service immediately, or within the first hour after your request has been sent.
Royal Mail OBA available services
Royal Mail Tracked available services