Thanks Guys, for all your input.
The icons I'm asking about don't show in Icon or List view. They do show in CoverFlow view where, if clicked, they actually do something, however, in Column view, they do nothing. But the same icons can be reached by control clicking the file name in Column view and selecting Quick Actions in the contextual menu. So, I reckon it's a fault with Tahoe that the icons show in Column view but don't actually do anything.
On a similar note…
When I select a music file in Finder and Get Info (CMD + I) I'm not able to alter any of the (Metadata?) information shown - eg, on a music file, under More Info, I want to change either the title or the author, but they're not selectable. On a Windows machine, I can Alt + Enter to bring up the info pane where I can alter the Album, Album Artist, Track № etc. Is there no way to alter these items on a Mac by using Get Info or some other way? And under General (in the Get Info pane), what do the selectable boxes next to Stationery Pad and Locked actually do?
Thanks