This definitely is a Cymbidium and not overpotted in my opinion. It also definitely has scale. I do not know if you can obtain in Australia a product called Bayer 3 in 1 Miticide/pesticide spray? It is available over the counter here in California. If there is an equivalent for scale in your country, it will be what you need as you have a severe infestation. Alcohol and cleaning the bulbs and leaves will not stop it although it may slow it down.
A fungicide will not kill insects or bacteria. An insecticide will not kill fungus or bacteria. Be specific in what you use for which problem. There are some sprays which combine to get all three. Just read your labels carefully.
Good luck