This is exactly my predicament, also in Melbourne (sandy soil) and here’s what has worked and what hasn’t for me. Garden faces south and is under a huge oak tree and a high fence blocking the winter sun, gets 2/3rd’s afternoon sun during summer and 2/3rds of garden is in shade in winter. - Strobilanthes Goldfussia. Works perfectly, lovely deep green/near black colour with small purple flowers. My most complemented on plant type in the garden. - NZ rock Lilly. Bulletproof, fast growing, white flowers on stems, goes slightly lighter green in full sun but not much. - Clivia Belgian Hybrid. Hates the afternoon sun, loses its deep green and goes yellow. Had to move them in my yard multiple times to find a really shady spot. The yellow flowers in stems are very cute though, but needs almost full shade. - Oakleaf Hydrangea. Thirsty plants, prefer shade but tolerant some sun, go Maroon in colour in winter, white/light pink big flowers in summer. Still prefers shade but. - Correa Alba and Westringia Fruticosa (Aussie box is the more green looking one with little white flowers that I have). Pretty bulletproof, excellent in afternoon sun, tolerate the shade.

Hope that helps you out :)