I disagree with your stmt,... identifying ... accessing .. public service ... basic.  If you don't normally need to identify yourself getting on a bus, going to the library, etc then the person must be allowed to continue wearing the niqab.  However, if you are getting on a plane, renewing your drives licence, testifying in court then the person must remove the niqab so that they can be identified.  My understanding, the niqab is removed in Pakistan courts.