A single new artist produced all twenty-four sets in this series; let's call him "D" for convenience.
Note that the copyright date on the cards is 1970; this clearly refers to the copyright of the concept of Mini-Toons, which were first produced in that year, & not to the date of publication. The copyright date on the transfer sheets is 1971.
We know some, but not all, of the serial numbers; however, they almost certainly cover the range GK81 to GK104.
Also interesting is that the unused sets we have are a later printing than the used ones, which disingenuously ask you to "collect all 24 titles" — when, of course, there are 48.
Picture Credit: The SPLAT Scan Archives, with thanks to Joe Robinson
© Tom Vinelott 2018