As many of you will recall, decades ago D.C. Thomson always used to promote new comics and free gift issues by including four page A4 inserts in the centre pages of The Dandy and The Beano. (An idea also later used by IPC.) These inserts were printed in navy blue ink on pink paper so they always stood out. Their design was a masterclass in how to sell a comic, with dynamic layouts, exciting logos and announcements that were hand lettered to great effect.
Here's one of those inserts that would have appeared in either The Beano or The Dandy in September 1966. (I kept the ad but not the actual comic!) I can't remember if I bought The Hotspur that week. I didn't really follow that comic until 1969, but the advertised stories Test Pilot Z and The Black Hawk sound intriguing.
I understand that these four page inserts (often thrown away) are now more collectable than the issues they appeared in! I kept a stack of them for years then foolishly used them as firelighters ages ago!