the scan is not really for the Channel 8 version of the game. The cover graphics are from the Channel 8 package, correct, but you will surely notice the white stripes on the cover where other info used to stand. In the lower right corner Channel 8 used to write "Mysterious Adventure No. 1" and just underneath the game title "The Golden Baton" it usually read "from Channel 8 software". If you take a look at the catalog scan for "Arrow of Death Part 1" you can also see "The Golden Baton" and "Arrow of Death Part 2" covers. Both have the Chanel 8 company info right underneath the title.
So this cover scan here has re-used graphics from an old Channel 8 clamshell release. As far as I know this version here is a so-called Dixon's Pack. And publisher is most likely Adventure International UK, because they re-used the Paxman and Channel 8 packages, probably bought up their stock.