Problem using --profile-dir while working in home directory
When downloading radio programs, I like them all to go into one single directory, with a fileprefix of "<longname>< - episode> (<pid> <version>)".  Example: "Absolute Power Series 4 - 3. Episode 3 (b0192y9d original).m4a".

When downloading TV episodes, I like them in separate subdirectories, e.g.: "Pointless Series 18/44. Episode 44.m4a".

To facilitate this, I have two profile directorys: /home/pi/.get_iplayer and /home/pi/.get_iplayer_tv.  When downloading TV,I add "--profile-dir=/home/pi/.get_iplayer_tv".  The options file for radio has the fileprefix mentioned above.  The options file in /home/pi/.get_iplayer_tv has a fileprefix of "<episode>".

On Windows, this works as expected.  On Linux though, my files are split into subdirectories, but use the fileprefix option from the wrong profile directory.  E.g. filenames come out as "Pointless Series 18/Pointless Series 18 - 44. Episode 44 (b09ptth5 original).m4a".  I have no idea why get_iplayer would read both options files in the first place, let alone prefer the fileprefix option from one over the other.  Any suggestions?
Have a look at presets. You can have one profile directory,but apply different sets of options as you choose using presets. I won’t repeat the manual here, but please ask if you get stuck.

Thanks, I obviously completely missed presets in the docs. Works great.
You fell foul of the fact that get_iplayer also loads settings from a local options file (./.get_iplayer/options) if it exists, which is true if you are working in your home directory. I had forgotten this behaviour was still in get_iplayer, so I'll likely remove it in the next release. A preset will work just as well, and you should be able to use --profile-dir without such potential side effects, even if you are working in your home directory.