But @ArcheryAnnie i agree you can do all that in the UK but it's not as good
Eat out - course you can but it's always very expensive for much lesser quality food. Eg fresh caught fish in Cuba maybe works out at £5, fresh caught fish in Woolacombe £15.
visit local historical sights (Pompeii for example) - yeah you can visit historical sights but you pay ridiculous prices to get in, ridiculous prices for any kind of tour, HUGE mark up on any food or drink you want to buy there and you'll probably be in the pissing rain. It's not a relaxing experience lugging round warm sandwiches and drinks so you dont have to take out a second mortgage to have lunch there and carrying a coat just in case.
walking tours round cities where you pay what you think the tour was worth at the end - in the uk they will have a set (expensive) price and will also probably be in the pissing rain/carrying a coat
Boat trips - cold, wet, windy, expensive. Probably in a winter coat. Cant spend the day leisurely swimming of the boat, sunning self on deck in bikini drinking wine, swimming and snorkeling through crystal clear waters seeing exotic fish and diving through caves.
SUPing, kayaking - expensive to hire the gear, probably also need to buy or rent a wetsuit and water shoes as it will be cold, wet and windy.
Exploring new towns - yes you can do that in the uk.