The dates of the Perth Modern School test can be found through the Department of Education Gifted and Talent Website here: http://det.wa.edu.au/curriculumsupport/giftedandtalented/detcms/school-support-programs/gifted-and-talented/application-information/key-dates.en?cat-id=2058768#toc2

According to the downloaded document, the date of the GAT test is Saturday 11 March 2017 for metropolitan and Bunbury and from 13 to 17 March 2017 for country and regional areas.