Complex sentence: The mansion later became an orphanage run by Barnardos until the 1970s when it was demolished to make way for the Woodlandsgate estate built by Barratt Homes.
Split into simpler sentences: The mansion later became an orphanage run by Barnardos until the 1970s. It was eventually demolished to make way for the Woodlandsgate estate built by Barratt Homes.