I dont know what this is @HelenCross and I have not found anything in 'Medicine of Australian Mammals' which would explain both conditions together. I will pass your photos to some national experts but I suspect they would want a close inspection before diagnosing. There is no obligation on anyone to take action because it is wild (different with a captive animal or a research animal) but some people would want to kill it, or to capture it and take it to a vet, much as some people do regarding wild wombats with mange. I understand it is on private property, which may further restrict who is willing/able to respond. Would you like to message me about whether you want to take the next step and if so whether you need any help to find people with relevant skills and licences to do a pre-mortem or post mortem examination?