No, it is not intended for use by ordinary persons, the main switch in the CU is intended for use by ordinary persons. The main switch in the CU covers the regulation you posted above. Anything else can be single pole and not contravene any regulations.If the DNO fit an isolator in the meter box of a house it is obviously intended for use by ordinary persons so it MUST break all live conductors, Makes no difference if the main switch in the customers CU does as well, If the DNO fit a switch, and it is intended for use by ordinary persons, then the reg applies..