Vehicle importation

"Alf Delany wished to attend an event on the River Bann in Northern Ireland. In order to drive his car over the border, he had to temporarily export it to Northern Ireland, and then re-import it into the Irish Free State. The rubber stamp advising that the car must not be modified, or maintained while out of the Free State seems to be a strange requirement. The paperwork to return was different. There ere only a limited number of approved crossing points. "