The Horniman Museum, best-known for its walrus and aquarium, also has a rather wonderful Victorian conservatory. It was built in 1894 for the Museum's founder Frederick John Horniman, and originally located in his Croydon garden. He built it for two reasons: to house his own collection of rare plants, and to provide his elderly mother with a comfortable garden environment. After his death it gradually fell into disrepair, but moved to the museum grounds and underwent conservation in the 1980s.
The conservatory is cast iron, the work of leading company Walter Macfarlane & Co. They sent the cast sections by train to Croydon, where local contractors Joseph Kemp & Son assembled them. The resulting building is light and romantic, full of pleasing details. It's no wonder that the conservatory has become a popular venue for weddings and events.
Further reading: there is a detailed description of the conservatory here.