Thank you to everyone who replied to my previous post about Ugg boots. I decided to buy a pair of Kiwi boots: the ultimate tall boot. These have a very thick sole and a deep toe-box so there is lots of toe wriggling room. The company was very helpful when I contacted them about sizing and the boots arrived in 5 days which is excellent for rural mid Wales. The boots are excellent! Apart from needing a very thick sole when I am out, I also have quarry tiled flooring in the kitchen which is extremely cold. I have 2 thick hearth rugs in the kitchen, one by the sink and another by the work surface, but I still have to walk around and my toes were really suffering. That is now in the past. My chilblains have almost healed and I am able to go for walks which has also improved my circulation. I no longer feel a prisoner in my own home.
I also bought some Warmerwear battery heated socks. With ordinary batteries they were hardly warm at all, but with the recommended batteries they really heated up. They use 6 AA batteries, 3 in each sock, but at £13 for 12 batteries they are not cheap to use.