Conservatories full of sun
Conservatory is by definition attached to a house and that makes it perfect for... anything we want. It may be small, long, wide, or huge, you can make it any way you want and your space allows. Since the point is to have a bright space, white and other bright colors are natural choice when designing it. Another nice thing about conservatories is that you can make it as a visual extension or in totally different style with its own character like this example by Vale Garden Houses.
Since your conservatory is an extension, it would be good to leave outside walls intact, especially if bricks or stone are visible. That will create a warmer atmosphere that will define the overall look of the space. As the photo by Gary Quigg is showing, you really don't have to add many details to it. Go with natural, earthy colors and furniture that incline to rustic or even slightly French style. Put a nicely designed fireplace and that's a perfect place for family gatherings.
The point of a conservatory is to have light coming in from all sides possible but if you want some privacy if your yard is open to others, roman blinds are good choice. They are easy to operate and won't add too much weight to overall look. Mark Pashley decided to go with beige and brown colors naturally connected with blinds, creating an inviting space for the whole day that most probably looks warmer than your living room.
To make the connection with the surrounding nature complete, put some plants in your conservatory, like this example from B. Jane Gardens. Here you can design in reverse: first decide how many and what plants you want in, put them in place respecting their needs for light, and then choose furniture depending on the remaining space. That may sound like an upside-down process but as a matter of fact it may make the whole process easier because the point is to make a connection with nature, not a room full of furniture.
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