The obvious point is that Durham teaches the laws of England and Wales and Monash etc teach the laws of Australia (Federal) and of the Australian States. Although the laws of Australia and its constituent States are derived from the laws of England and Wales, and Australia is one of the most influential common law jurisdictions, its laws are not identical to those of England and Wales. There is of course a lot of crossover, and it's not unusual for people who have trained as academic or practising lawyers in Australia to work in the UK academic or practising legal scene, and vice versa.
IIRC, Monash is one of the best universities in Australia. Monash is probably more like the Oxford or Cambridge of Australia than the Durham of Australia.