Went last summer on Princess.
At Edinburgh port did the Brave Heart excursion to Sterling Castle, people that went to Edinburgh Castle and Sterling told us Sterling was the better of the two.
Glasglow port went to the Highlands Loch Lomond and the castles.
Belfast went to The Giants Causeway, one of the wonders of the world. If you go have lunch at the Inn. The tomato soup is outstanding. The site is in the village of Bushmill where they distill the famous Irish Whiskey.
Dublin we went to the south through the countryside. Had Irish stew at a local pub. Very good.
Holyhead, Wales took the rail trip in to the mountains at Snowdonia. great trip.
We visited the Orkney Islands, can't comment of Crnwall.