We did Dublin on our own with a taxi ride straight to the Guinness Factory (very interesting, even for a non-beer drinker), then we walked and walked the city with stops at various points of interest, including Trinity College / the Book of Kells (do take a tour with one of the students, ours was entertaining and informative) and save some time to experience Dublin pub-style. We took a taxi ride back to the ship for even less...we always asked the price before getting into the cab. (The taxi was less expensive for the 4 of us than it would have been to take the shuttle and we got picked up and dropped off where we wanted.)
We really wanted to go to Wales, so contacted the Liverpool Tour Guide Service (email@example.com). Hilary was our contact and she set us up with a wonderful guide named Judy Brough (http://www.guidenorthwales.com) or contact Judy at: firstname.lastname@example.org Judy went out of her way to try to fit in all our requests, letting us know when we could take time to 'smell the roses' and when we should increase our pace. Judy spent the whole time with us, even strolling with us around the Bodnant Gardens, Conwy Castle ruins and walking the town walls giving us information and answering questions as necessary and stopping for as many photo op requests as possible. We spent a great 9 hours with Judy—she even brought the blankets for our picnic lunch. Awesome, awesome!!
We pre-booked Sean from Ireland Belfast Tours: http://www.irelandbelfast.com or contact Sean at: email@example.com). Sean was great at communicating by email before, during and even after our cruise giving us a list of sights we visited in case we couldn't remember them all (which we couldn't). This was our only day of rain and it made the beautiful green, misty views feel very Irish. Sean helped us accomplish a long list of sightseeing goals in a very colourful, funny and informative manner. Entertaining!!
Our group of 4 had toured Edinburgh before and we wanted to see more of Scotland on this trip so we hired Duncan McNab: http://www.tours-from-edinburgh.com for the 2 ports of Greenock & South Queensferry. I immediately knew we would like Duncan when he responded to my first email's huge wish list of sights by saying "no problem...if I hire a helicopter!!" See more information under Greenock, above. We highly recommend Duncan!!