This is a single specimen a few metres from the river bank. I have not seen others in the region but it was easily overlooked except when in flower. I am not absolutely sure about the species.
The other possibility Prostanthera cuneata, which is highly aromatic, the branchlets densely covered in spreading hairs. It usually occurs at over 1500 metres. Phylicifolia is slightly aromatic, the branchlets sparsely covered in hairs. According to Vicflora, both species have purplish dots in the throat of the flowers, as well as yellow dots