We had pre-paid for fuel and coasted into the Dublin airport with about 1 liter remaining. The Transport used diesel and the typical cost in Ireland was $8.26 per gallon.
Enterprise didn't blink at what was left of the Transport and even reimbursed us for the replacement tire.
We took Ryanair from Dublin to Edinburgh. For all the hoops that Ryanair imposes on you to buy a ticket, the airport experience was typical airline. Their check-in area was well staffed and moved quickly. Of course, the flight was late but every flight we took was late.
Seven of us flew from Dublin to Edinburgh for a fraction of what we paid per person for Memphis to Dublin.
The Irish airport security (think US TSA) was disorganized and the only difficult clearance we had on the trip.
In spite of the UK's leaving the EU, there was no security, immigration, nor customs for our Ireland to Scotland flight upon our arrival in Edinburgh.