(Having said all that I used to read John Craven's Back Pages in my younger days! And somehow always imagined that Biddy Baxter personally wrote the Blue Peter billings!)
She probably did, actually, in the old monopoly days the billings used to be very idiosyncratic, the likes of Not The Nine O'Clock News ("Maen Nawr O'Gloch!"), Carrott's Lib and There's A Lot Of It About ("This week, Spike Milligan will be discussing 'does size matter?' with four beautiful naked women and definitely not watching this programme which isn't half as interesting") clearly used to put their own billings together themselves. Even Grandstand used to get some quirky billings ("Bob Wilson has a bigger postbag than Madonna"). Clearly when the other magazines started up they couldn't do it anymore.
The problem with the daytime listings is that it's simply illogical to have the daytime listings from top to bottom and the evening listings from left to right. And while having the choices on a double page makes some sort of sense, it's impractical having to flip backward and forwards from the listings, especially as the design of the choices spread - they're not in any kind of time or channel order - makes it hard to find them anyway.