Although it's an episode guide, it's also reviews and commetns about the programmes - useful if you want to know more about programmes you haven't heard.
Reviews and comments about almost every BBC radio comdy programme of the 1980's and 90's; an excellent referecne only let down by being hosted on AngelFire which has more pop-up advertising than you can imagine.
Old Time Radio (OTR) isn't a field I go into very often, but this is the major reference for the subject, and sometimes they do stray into New Time Radio.