how long do you think it would take to task a UK-based aircraft (probably from Caernafon) to fly across Ireland, refuel and then go to the FV compared to tasking the Sligo aircraft to something that might technically be outside their area?
The Dublin helicopter was 140 nm from the refuelling site at Blacksod. Caernarfon was 70 nm further away. So the answer to your question is that the extra travel time involved would have been approx 30 minutes.
My point is not about taking Sligo out of the picture. I can see why Sligo would have been tasked, even if HMCG was the principal mover.