The files saved directly to FAT are in +3DOS format. I think for what you are trying to do is best to use a .TAP container, like this:

.tapeout myprog.tap
SAVE "myprog"
.tapeout -c

Then move the file myprog.tap to the PC and load it using the emulator.

I then connected the DivMMC and loaded the physical audio tape into the datacorder in USR 0 mode, after which I used SAVE * "FOLDERNAME/FILENAME".

When I load up the emulator I see the programs in the correct folder, but they have no extension and they won't load. The emulators I have tried are Speccy 2.2 and the standalone emulator supplied with 'Sinclair Spectrum Allstars'.

Am I right in thinking that I need to specify an extension during saving to SD card from BASIC and, if so - which extension(s) do I need to use?

P.S.   Snapshots are working on both the +2B and the Emulator with no problems.

P.P.S The wiggling chin animation in the "We Are Alive" demo is awesome!