The get_iplayer utility enables you to download content direct from the BBC's iPlayer database. However it only seems to allow you to access current material. Beyond a certain date in the past, the material - although available to view on iPlayer using your browser - is not listable or accessible using get_iplayer.
For example, this programme:
http://www.bbc.co.uk/programmes/p004y26w is available to view on the BBC's website, but only the current episode of "In Our Time" appears to download from get_iplayer.
Has anyone encountered an option that allows you to download older material? It's clearly accessible from the website. Perhaps it's contained on a different database that get_iplayer cannot access?