There is a campsite in Cornwall that has a number of Yurts perminantley pitched. I have never been there so can not say if it is any good or not
Yurt holidays @ South Penquite Farm
Also this site list campsites in the UK and you can search on amongst other things if they will allow fires
The UK Camp Site for Tent and Caravan Campers in the UK
Again I have never used this site so no idea how good it is