Public interface is not working

The public interface ID # ref number can be issued to e.g. EC internal staff, and then re-issued to a member of the public. Need to prevent the re-issuance of the ID

Start by locating where public interface IDs are issued and where an existing ID is checked before re-issuance. Reproduce the case of an ID issued to EC internal staff and then requested for a member of the public; done means the system prevents that re-issuance and verifies the behavior with the relevant tests.

Written by the indexing model from the issue text.