There is no automated system between the Irish and UK banks. PTSB will have had to physically send the cheque to the UK bank, they will process it at their end, give it the standard time for it to be bounced if needed and then revert to PTSB to say funds are cleared (normally by a physical letter which they send back to PTSB) and then transfer those funds to PTSB. AIB state 4 weeks, not sure about PTSB. It's an old manual process,