I've received an auto-reply from POTW:

Thanks for your email. Unfortunately because of the volume of email we receive, we can't guarantee to read and reply to all of them. http://www.bbc.co.uk/radio4/factual/pickoftheweek.shtml

However, if you need a reply to a specific query, please visit the Radio 4 Contact Us page http://www.bbc.co.uk/radio4/help/contactr4.shtml