Holby fictional hospital within the city in which "Casualty" and "Holby City" are set. It is based on the Bristol Royal Infirmary which the original script writers spent time observing in the 1980s in order to garner ideas for "Casualty". Although both shows are set in the same hospital, "Casualty" is primarily filmed in Cardiff, whilst "Holby City" is filmed in Hertfordshire at BBC Elstree Centre. The indoor shots for the first series of "Casualty" were filmed at BBC Television Centre in London. The exterior shots of the hospital used in "Casualty" were formerly filmed at the City of Bristol College;
Characters of Holby City the characters gathered together in the hospital bar at the end of the episode, and raised a toast "To the one and only Sandy!" Estelle "Essie" Harrison, played by Kaye Wragg, made her first appearance in the sixteenth series episode "My Name Is Joe", which aired on 6 May 2014. Essie is a Staff Nurse at Holby City Hospital. She came to the hospital with her dying grandfather and she started a relationship with Sacha Levy (Bob Barrett). She later moved to Germany after her grandfather died. In October 2014, it was announced that Wragg would be returning to "Holby