Those considering a home expansion have a wide variety of choices. You really shouldn't restrict yourself to a conservatory. Some alternatives to a conservatory include:
Orangery: An orangery is a sort of sunroom that is often spoken in the same breath as a conservatory since the two are so similar in appearance and function.
Garden Office/Garden Room: They're perfect for creating a different location within your home.
Veranda: A veranda can add a touch of class and sophistication to any home. They are open and airy, thanks to the huge windows, bifold doors, and uPVC bars.
Pergola or Canopy: If you already have a patio installed in your yard, a pergola or canopy may be the best way to make it larger.