I have copies of the tracking book, one on fishing and another on poisonous plants. I have had them longer than I rember, but I bought the poisonous plants one when my boys were little: they are now in their 40s!
Like you I tried to find out if they were still being published with no joy whatsoever. I hope you get a more helpful response than mine as I'd like to get hold of some more for my granchildren.
Thanks for posting.