Ashwood Shepherd Huts
I keep coming across these guys. They are highly spoken of. Shepherd huts can look a bit samey on the outside, but you really notice the difference when you go in. Ashwood, a friendly family run business have got it exactly right. They have a range from simple to luxury, to me the simple felt luxurious.
Everything well-proportioned and great use of space make them feel roomy. They will work with you to create bespoke unique adaptations to suit your needs. There are nice images on their site that give you a good idea.