Would you not be better renting a "holiday cottage" for a week?
I think if you rent a non holiday cottage you might not be able to do it for just a week,most rented properties are a minimum of one or six months.
Have a look here:~
http://www.english-co...tages/pages/home.aspx
this is the website of one of the largest Holiday Cottage companies,where you CAN rent for just a week.
However,as we are now getting close to Christmas your choice may be limited.
Have a look anyway,you never know what you may come across.
Good Luck.