Also 10-32 UNF is the same as M5.
Links to Ebay would help others, I like the solution.
Colin
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Here's some links to the specific items but, when they eventually die, searching the descriptions should also yield results.
M3 M4 M5 Stainless Steel 304 Exhaust Manifold Studs Double End Threaded Rod Bolt | eBay
Blind Hole Aluminum Alloy Knurled Thumb Nuts M3M4M5M6M8M10 Hand Grip Knobs Nut | eBay
I think you will find that 2BA and 5mm will readily interchange - but the threads are not making very good contact.
Just got a couple standard 5mm x 40mm steel knurled thumb screws from an engineering supplier on ebay, perfect fit. I'm sure similar would be available in Aus.
https://www.ebay.co.uk/itm/385140502427
Best wishes from Scotland