I agree, I don't see why Australia would bend over backwards for the UK (or anyone else for that matter).
But the UK and the EU have been talking free trade deals. Which is funny because they were Trump back in the early 1960's when they decided to wall themselves off from our apparently fearfully extremely competitive agricultural and manufacturing sectors with trade walls.
The EU pursues $15b free trade talks with Australia, but there's a catch
EU talks with Australia and New Zealand deal blow to UK free trade plans
I don't see some Wedgetail, another 25 Bushmasters or some Banannas being enough. Some lop sided freetrade deal isn't nearly enough.
While Australia is spending the money, Australia strategically is in a much better position than the EU. Our economy is growing, our trading partners economies are growing, we are surrounded by developing nations that are growing much faster. We have a very complimentary economy to Indonesia, India, China etc.
We aren't just buying a OTS design, there will be ongoing development etc. Eventually who ever wins will have to have a significant local footprint, with local people in Australia and their people in Australia. This will likely become as big as their home design team. I feel annoyed that they are using the defence deal as a economic negotiating tool.
So they are only military aligned with us as long as it economically profitable for them. Sounds like the worse fair weather alliance ever.