Question: Durring what era was the public state school in Adelaide, South Australia adjacent to an Anglican church in Kensington formed?

Context paragraphs:
Pulteney Grammar School: Pulteney Grammar School is an independent, Anglican, co-educational, private day school.  Founded in 1848 by members of the Anglican Church of Australia, it is the second oldest private school in South Australia.  All campuses are located on South Terrace in Adelaide, South Australia.

Marryatville High School: Marryatville High School is a public state school in Adelaide, South Australia.  It was formed in 1976 during the Don Dunstan era of South Australia from the amalgamation of the Norwood Boys' Technical High School and the Kensington & Norwood Girls High School.  The school is situated on a large area of land in the eastern suburb of Marryatville, part of the City of Norwood Payneham and St Peters.  First Creek cuts through the school grounds and large gum trees line the property.

Anglican Diocese of Adelaide: The Anglican Diocese of Adelaide is based in Adelaide, South Australia.  The diocese is a part of the Province of South Australia of the Anglican Church of Australia and a part of the Anglican Communion.  The diocesan cathedral is St Peter's Cathedral, Adelaide.

St Matthew's Church, Kensington: St Matthew's Church is an Anglican church in Kensington, an inner eastern suburb of Adelaide, South Australia.  It is adjacent to Marryatville High School.

Mark Lawrence (bishop): Mark Joseph Lawrence (born March 19, 1950, in Bakersfield, California) is an American Anglican bishop.  He has been the bishop of the Episcopal Diocese of South Carolina since 2008.  In November 2012, the diocese under his leadership withdrew from the national Episcopal Church to become an independent Anglican diocese and eventually came under the oversight of the Anglican Global South.  The national Episcopal Church does not recognize this diocesan withdrawal.  Instead, national leaders of the Episcopal Church consider Lawrence to have abandoned the Episcopal Church and his position as diocesan bishop.  According to the official website of the global Anglican Communion, the independent diocese under Lawrence's leadership is not a member of the communion.  However, the Steering Committee of Anglican primates of the Global South recognized Lawrence as bishop over a diocese "within the Anglican Communion" in December 2012 and recognized the diocese as part of the Global South in August 2014.  The status of the Diocese of South Carolina is currently the subject of state and federal lawsuits, but is settled in terms of canon law.  [Some debate this, as ACNA canon law does not apply to assets belonging to The Episcopal Church.]  Lawrence and other bishops in the Diocese are now formally affiliated with the Anglican Church in North America upon the unanimous admittance of the Diocese of South Carolina on 27 June 2017.

Holy Trinity Brompton: Holy Trinity Brompton with St Paul's, Onslow Square and St Augustine's, South Kensington, often referred to simply as HTB, is an Anglican church in London, England.  The church consists of four sites: HTB Brompton Road, HTB Onslow Square (formerly St Paul's, Onslow Square), HTB Queen's Gate (formerly St Augustine's, South Kensington) and HTB Courtfield Gardens (formally St Jude's Church, Kensington - officially in the parish of St Mary of the Boltons but part of HTB), as well as being the home of the St Paul's Theological Centre and the Alpha Course.  It is where the Alpha Course was first developed and is one of the most influential churches in the Church of England.

Province of South Australia: The Province of South Australia is an ecclesiastical province of the Anglican Church of Australia, the boundaries of which are those of the state of South Australia.  The province consists of three dioceses: Adelaide, The Murray and Willochra.  The metropolitan of the province is Jeffrey Driver, Archbishop of Adelaide.

St Paul's Church, Manuka: St Paul's Church is an Anglican church in the suburb of Griffith in Canberra, Australia.  Founded in 1939, it is part of the Anglican Diocese of Canberra and Goulburn.  It is listed in the Australian Capital Territory Heritage Register as an "...excellent example of an Inter-War Gothic church with Art Deco influences".  It was the first place in Australia to install a combination organ and has the only peal of bells in the Australian Capital Territory.  It was the first Anglican church to be built following the foundation of Canberra as the national capital (St John's in Reid having been consecrated in 1845) and is the first Anglican parish in South Canberra.  It is situated on the corner of Canberra Avenue and Captain Cook Crescent, opposite Manuka Oval and the Manuka shops.

St. Mark's College (University of Adelaide): St Mark's College is a co-residential college in North Adelaide, South Australia.  Founded in 1925, it is affiliated with the Anglican Church of Australia, yet accepts individuals from all faiths.  It is the oldest residential college associated with the University of Adelaide and also accepts students attending the University of South Australia and Flinders University.

Anglican Diocese of Willochra: The Anglican Diocese of Willochra is a diocese of the Anglican Church of Australia located in the state of South Australia, of which it covers over 90%, mainly in northern and western South Australia.  The diocese is made up of thirteen parishes and five ministry districts comprising 80 small congregations.  It was created from the Diocese of Adelaide in 1915.

Supporting paragraphs: St Matthew's Church, Kensington Marryatville High School
Answer: Don Dunstan