So it is much as I thought, the banks have not yet bothered to add the capability to 'Block' a OP/ DD, even do their own rules allow it. The UK (BACS) version of the system works differently. The originator first has to send a 'electronic' mandate to the bank to set up permission for the DD. The Irish version just requires 'OP/' to appear in the DD’s on the narrative field.
Towger.