Yep, it's due to Sepa, I called them last week and had to cancel a DD by phone, in fairness they were quick and helpful on the phone at least. Fyi I've seen delays on other DD's due to Sepa, was from AIB to UB, so not sure at which end it was delayed
My money is on Ulster Bank being the cause of the delay. I suspect he reason may be that their IT being tied up with RBS. Chances are they are struggling to get SEPA in properly.