Senior School

Peter Milligan

Acting Principal

MEdLead, B.Ed, Dip RE, Cert. III Sys. Theology, MACEL

Peter Milligan graduated from the Australian Catholic University majoring in English, History and Religious Education. He has been a member of the Executive, Acting Principal, Deputy Principal and Faculty Head in a number of schools. He has taught in New South Wales, Queensland and the ACT. Peter is married to Linda and they have two adult children, Joe and Anna.

Jane O'Brien

Acting Head of Senior School

BSc (Hons), GradDipEd, MSc

Jane studied Geology and Zoology at the Australian National University before spending time in Environmental Research at the Australian National University and working within the Mineral Resources Industry. Jane taught the Environmental Science Program and the Teaching Program at Monash University (Churchill) and the University of Canberra, before becoming a science teacher. Jane was Extension Activities Coordinator, Duke of Edinburgh's Award Coordinator and Head of the Science Faculty prior to becoming Director of Teaching and Learning at CGGS.

Tara Dunstall

Director of Studies

BA, LLB (Hons), GradDipLegPrac, GradDipEd

Tara joined CGGS in 2008 to teach legal studies after a career as a Senior Solicitor with the Australian Government Solicitor. In her time at CGGS, Tara has also taught business, commerce and geography. After a brief stint teaching business law at the Canberra Institute of Technology and communications at the Australian Defence Force Academy, Tara returned to CGGS and was appointed the Head of the Geography and Social Sciences Faculty in 2012. Tara acted as Director of Curriculum from April 2015 until she was appointed Director of Studies in October 2015.

David Blue

Director of Projects and Planning

BSc, DipEd, GradDipEd (Ed Comp)

Since joining CGGS in 2001, David Blue has been involved in the School in many ways. He has taught computing from Years 7 to 12, junior maths and is currently teaching physics in the IB Diploma Programme. As well as his current role as Director of Projects and Planning, David has had periods acting as Head of Senior School, Director of Curriculum and Director of Staff Services. David studied theoretical physics and mathematics at Flinders University. He taught at a number of independent schools in South Australia and Victoria. As a keen sportsman, David has coached soccer, basketball, rowing, squash and volleyball. David has held positions as Head of House, Head of Science, Head of Information Technology, Dean of Middle School and Outdoor Education Coordinator before coming to the ACT.

Jeanette Widmer

Director of Pastoral Care

DipEd, AdDipEd, Med

Jeanette graduated as a Physical Education teacher, then studied Special Needs education, Literacy and ESL,  with a major in Gifted Education. Prior to joining CGGS in 2001, she was head of faculty and head of house in schools in the ACT, South Australia and New South Wales. She consulted  for the Catholic Education Office in Student Engagement, lectured at the University of Canberra in Inclusive Education and has been a guest speaker at national conferences for Pastoral Care, 'Say No 2 Bullying' and girls' education.

Sarah Trotter

Acting Director of Teaching and Learning

BA, GradDipEd

Sarah undertook her Bachelor of Arts at the Australian National University before completing her Graduate Diploma in Education (Secondary) at the University of Canberra. She has worked in schools in both the ACT and in NSW. Prior to being appointed the Director of Teaching and Learning (Acting) at CGGS, she has been a co-ordinator for the Duke of Edinburgh Award Scheme, Religious Education (Assistant), History, HSIE, Humanities (Years 6-8), Integrated Studies (Year 7), Big History and the International Baccalaureate Diploma Programme.

Tina Twigg

Head of Boarding 


Tina Twigg joined the CGGS Boarding House in 1999 as Assistant to the Head of Boarding, later becoming Head of Boarding in 2006. In its first year, Tina was invited to join the board of the Australian Boarding Schools Association (ABSA) where she served until 2013. Tina is currently the secretary of the NSW division of ABSA. Tina and her husband Paul (who also works in the Boarding House and at the School), both reside on campus. They have two adult children, Jess and Andrew.