Hard to say exactly what's wrong with it on the information you've given - plants failing will often flower before they die. You don't say how long it has been in the pot or whether you feed it. I think what I would do, despite it being summer, would be to take it out of the pot and see if it is potbound and see if the watering it gets is penetrating deeper than just around the inside edges of the pot. If it is potbound, I'd tease out as many of the roots as I could, cut off at least an inch of them all around; refill with fresh, good quality, potting mix; balance the root trimming by cutting back the growth by about a third and keep it in a shady spot until it rocovers. Alternatively you could try slow release fertilser and see if it recovers but I think I'd take the more drastic action of repotting.

Temperate Vic is beyond my climatic ken or wants but none answer. I suggest 4 possibilities for leaf tip-and-edge die back:

a) Most likely you have been too heavy with fertilizer and burnt off the rootlets which take up water - hence water stress and leaf discolour and dieback. Repair by leaching with plenty of (not grey) water.

b) The plant is suffering from thirst/drought and again the rootlets from the one third of the plant below the ground are dieing back. Therefore water a-plenty once a week even if the Murray is dry - because winter rains are nigh for you southerners surely! Don't believe Howards blasphemous spin, god and history are on your side!

c) The plant has a fungal infection of the rootlets - usually Phytophthera species - which cause the same problem e.g. dieback in Citrus, avacodoes and WA Eucalypts. For repair ask at your local Dept of Ag or Nursery. There are a number of systemic fungicides which work commercialy here in the sub tropics but you live in a different climatic world. If you are a chemical hater use poultry manure because it has a magic factor which worked on WA Eucs but I am too obsolete to discuss.

d) and to confuse you, if you water too much the rootlets are drowned and the same can happen to the plant. Balance is flavour of the year; but how long is piece of string?

Take your pick and good luck.