I find the problem (we have a Springer Spaniel and might be getting a Border Collie next year) is not so much finding accommodation - as RRB says, the Caravan Club accept dogs - but finding lots of things that we can do when we get there. So many things are 'No dogs' or 'Guide dogs only', or there are dog bans on certain bits of beach which means we have to drive miles to find a really good beach, and we are not really interested in long cliff top walks as the main attraction of the day. I have not noticed anything in the CC bumph discriminating against any breed of dog.
I can recommend Cheddar Gorge and some of the Great Little Trains of Wales as a good, dog-friendly day out. Dogs can go in all the caves and on the bus at Cheddar, and the trains in Wales charge a nominal fare for dogs, Willow got her own ticket!