I'm not sure what else it could be. Streaky crown rules out Tawny; and it surely isn't streaky enough for Striated Fieldwren. The plant looks like Samphire or some other saltmarsh plant and I've seen LG in this habitat before.
Thanks for the replies everyone.
Here's a wider pic just in case anyone was wondering about the plants.
He vanished into those shrubs but this was taken at the Werribee treatment plant so there are some reeds in the area.