Bearleigh you asked upthread about what UK plants you can grow in Melbourne. Quite a lot, though much depends on soil - sand in my case. The rest depends on how much water you want to use.
Plants I grew in the UK and still grow here are Chilean potato vine, trumpet vine, bears' breeches, salvias, verbena bonariensis, pelatgoniums, thunbergia.
Roses and camellias do very well here, though I don't bother with them as I find camellias boring after the flowering, and only like climbing roses, a possum's dinner.
Looking around the garden, what I have a lot of UK house plants that can grow outdoors: clivia, aspidistras, swiss cheese plants, bromeliads, plectranthus, gardenias, hoya, this all down one side of the house, shaded by NDN's trees so spared the scorching heat that rakes the rest of the garden at some point in the year. If the image I've attached turns out right, that would be it.
Today I did something new - beheaded a very large agave attenuata that was ridiculously pot bound. I could make no headway with the roots, even with an axe, so had at it with a pruning saw, popped it in a pot of cacti mix and we'll see what happens. They look so exotic and are very easy to grow, though rather rampant.