Monocock - where are you starting from?
If you can take in the south west here is an idea - head first for St Mawgan or Perranporth. Either are close to Newquay and other lovely beaches, half an hour takes you to the Eden exhibition and there is the theme park for the kids. Maybe spoil yourself if you like seafood and go to Rick Steins. There is a large variety of local hotels. If you can persuade her in doors carry on tothe the Scilly Isles - its only a short hop over the sea for the interesting landing or if you cant persuade her lands end which has a good exhibition for the kids. If you havent been to Scilly Isles and want to go maybe on to Plymouth and treat them to a helicopter ride over the water. Again plenty to do for a few days in Plymouth. All in a good round trip for a week - hope it is of interest - let me know if you want any more info.