Yes, I agree with taking one's own kitchen tools, especially sharp knives, also a potato masher, pepper mill etc. A torch is also a good idea if you are very rural.
Waitrose definitely deliver around Devon and we place an order for things like toilet roll, dishwasher tablets, toiletries, milk, eggs etc. etc. to turn up an hour or so after our expected arrival time.
As BBbevan says, check whether the house will be decorated for you. I'd be surprised if it weren't, but best to find out first rather than have to rush out and buy a tree and decorations (we had to once!)
If there's lots of you, I recommend taking an extra bath mat as it usually gets well damp and smelly. If you have a dog, pack throws and blankets.
Hope you all have a great time.