If you fancy a cottage I have used these before and can recommend them
http://www.holidaycottages.co.uk/
We always have a week either in north Devon or Cornwall, Time seems to go much slower and we always have a relaxing time.
last year we stayed on a working farm, the farmer and his family stay in a big trailer home and rents his house out for the summer!
The kids loved it, we were welcome to walk around the farm and see all the animals.
feels a bit strange staying in someone else's home (they kept all there family photo's up etc) but i would definaltey recommend it.
Lots to see and do in North devon and some nice beaches too, although it does seem to rain a lot! but that could just be when I go!!!! (I'll give you the date so you can avoid:o))