Again — no information other than what you can see.
Clearly this promotion ran across several cereal brands, whose mascots are each displayed. The number "4" printed on the sheet is unlikely to refer to a particular packet back (as similar numbers have been used before) & is probably just the number of the sheet; from which we can conclude there were at least four sheets to collect!
However, I may be wrong; the use of puddles & fauna, etc., suggests a very specific use, possibly telling one chapter of a story — so perhaps there really were several different packet backs after all.
Picture Credit: The SPLAT Scan Archives
© Tom Vinelott 2020