We have found two good sources for booking quality small guesthouses and Bed and Breakfasts on the web. These are:
You can also access
information via Google Maps by typing in "B&B" or "Bed and Breakfast" when you have a map of the area open on your screen.
Generally you need to
book a cottage or an apartment for 3 or more days, probably a week in high season,
but for a family with young children this can be a great way of enjoying
The terms "Holiday Apartment" and "Country Cottage" and "letting" are used to cover the various options. Here is a good supplier in East Anglia
The largest supplier of campsite information is UKCampSite.