Yes I should have realised the difference. We always stayed at Isle of Whithorn and I forgot that Whithorn is a different place.
Just after I replied to you, I suddenly realised there was no harbour and I was several miles inland so worked it out for myself.
I was at Isle of Whithorn too earlier and had a wander around the harbour and a beer at the Steam Packet Inn. I can confirm there is no shop as someone I was talking to told me there is no shop in the village anymore. I'm sure the building probably still exists, I just wasn't looking for it.
Isle of Whithorn seems a much nicer village than Whithorn from what I seen.