Question: Walkley Heights, South Australia is located on land that formerly was a prison originally known as what?
Sentence (from "Electoral district of Playford"): Named after the long serving South Australian premier Tom Playford, it is a 22.7 km² urban electorate in Adelaide's north, taking in the suburbs of Ingle Farm, Para Hills West and Walkley Heights as well as parts of Gepps Cross, Gulfview Heights, Northfield, Para Hills, Para Vista, Pooraka and Valley View.
Relevant evidence: No