Is there a way of getting a list of old radio episodes (specifically PIDs)? It doesn't matter if they are unavailable, I am just after the tracklists

If it's tracklists for programmes you've already downloaded, you could search your history.
Change the search term from ".*" to limit your search to the items you want and use --listformat "<pid>" to return just the pids.

(16-12-2018, 08:50 AM)Is there a way of getting a list of old radio episodes (specifically PIDs)? It doesn't matter if they are unavailable, I am just after the tracklists

The listing archives here
https://www.radio-lists.org.uk/r3/
https://www.radio-lists.org.uk/r4/
https://www.radio-lists.org.uk/4x/
gives the pid in brackets for Radio 3, 4 and 4x