The Doctor watches Reinette walk across the grounds of the palace in episode 2x04 "The Girl in the Fireplace".
Source: The Doctor Who Locations Guide
Amy comes upon these simulated gardens while searching Two Streams for somewhere safe in episode 6x10 "The Girl Who Waited".
In front of the Hospital where Donna is staying in the computer simulation in episode 4x09 "Forest of the Dead".
From episode 2x09 "Something Borrowed".