Why do words fail you?.
Change the names to Joe Bloggs and Jim Crudd who have been having a legal todo. Each writes a book to put his side. Joe will write to show himself in the best light and Jim in the worst light according to what line each is attempting to peddle. Ditto with it the Jim and Joe way around. No surprises there.
This is interesting though:
Madeleine McCann Search Decision Support Document
"The reconnaissance undertaken and this report has been completed at the direct request and benefit of Guillhemino Encamacao the Algarve Regional Director of the Portuguese Judicial Police"
http://www.mccannpjfiles.co.uk/PJ/MARK_HARRISON.htm
No mention by name of Boogah Man I that I can see.
As I've understood it, by Portuguese law, you've hit on something that, by Portuguese law, Amaral might have been able to use in his defence, but for one thing.
What you outline is what is, I believe, referred to in Portuguese law as
to s/he who is willing, no harm can come, which enunciates precisely that principle: Kate wrote her book and Amaral his.
That creates a situation of annulment of the usual rules of libel.
However, what spoils it for Amaral is that he was demonstrated to have breached secrecy by publishing details of his book before secrecy was lifted.
Otherwise, he wouldn't have lost (at least the first round).