Carrickfergus’ main Post Office has been, not in the town centre, but within the local Co-op Supermarket which is across a very busy main road and acros the harbour carpark so not at all convenient to the townsfolk. That’s how its been for some years now but, that being said, there’s plenty of parking available the office itself is a good size, usually 3 or 4 windows open. Handily enough you can use the supermarket trolleys to transfer large and heavy parcels to and from your car therefore gets my vote for convenience in those circumstances.