I found this Trish .........
Wallaroo - AMS. Collided with US Liberty Ship and sank off Fremantle 11/6/43
Then I found this ....... with a bit more information !!

11 June 1943
HMAS WALLAROO, (minesweeper) sank in a collision with the American merchant ship HENRY GILBERT COSTIN 60 miles west of Fremantle WA. 3 ratings lost their lives.
12 June 1943
The minesweeper HMAS DUBBO, (LEUT N. G. Weber, RANR(S)) picked up survivors from HMAS WALLAROO sunk in a collision west of Fremantle WA. Three of WALLAROO’S complement were lost in the sinking.
Sorry K ... I didn't read your post properly !!
