Now I'm really confused. A pound in the UK doesn't necessarily buy what an AUD buys in Oz (yes there are coincidental exceptions, but it ain't the rule by any stretch!), or what a $US buys in the US. The price of goods and services (or if you like, the "cost of living") is highly variable between the 3 countries, even if you had a universal currency. A 1 to 1 comparison is meaningless. An exchange rate comparison on it's own is also meaningless. As is a gross income comparison. Anyone flying LH will be able to tell you that!
Yes there are 2 discussions here. Whether Jetstar pilots are more "competitive" in terms of what they cost the company, and whether Jetstar pilots are on good pay & conditions for a comparable LCC. Two quite different answers I suspect.