Hi Linz
You could go to Dublin for a couple of days from Liverpool or Holyhead - Liverpool is the longest ferry journey but the boys will enjoy it.
Don't know the cost, but travellodges are about 35 euro per night, and there are lots of
B & Bs.
You can see Dublin on the tour bus, theres lots to do and see. Check ferry crossings for a mid week or two day special price etc.
Julie