Given that the cache update in now weekly by default, the before and since options are going to be of less use having a seven day granularity.  The --available-since option already exists, can there also be an --available-before to allow a delay before attempting a download (in the past I've had low quality radio downloads when the PVR runs and the the program has only just been added)

Maybe. What you say makes sense, but I haven't had time to think about what to do with that group of options.

EDIT: After looking into this, I don't think --available-before would help. Even though the available streams might be update, the progamme availability date may remain the same.