Thanks Downunder and Cosmick. I bought a second one from Anaconda so I've done OK overall. I thought BCF's price was reasonable, so I'm not comfortable trying to get my $40 back just because I could have done better elsewhere. Caveat emptor as the Romans used to say.
KR - Both my Marlin 150;s have a whistle and a backup inflation tube. I'm GA and don't know about a TSO, but as long as they do the job that's good enough for me.
Old Koreelah - I borrowed a couple of jackets for my last trip to Rotto. They were airline type in sealed plastic bags, which is OK if you're above 2,000 feet as legally you don't need to wear them, just have them available. But just try and put them on in a cramped cockpit on your way down from 2,000 feet in an emergency, or in the water after the crash, and see how you get on. At least with these I can put them on before taking off. Cheap insurance. I do have a top tier aviation life jacket (ex oil and gas industry) which has a re-breather unit that would allow me to stay underwater for up to 10 minutes, but it's bulky and without training I wouldn't like my chances. I'd wear it crossing Bass Strait or Spencer Gulf, but for a 15 minute over-water flight within sight of land the Marlins should do the job.