Without the agreement of Paul Stephenson, the Met Commissioner the review the McCanns requested couldn't happen. Given that the Home Office agreed to fund it, Stephenson agreed to it going ahead. He said; " Sometimes we need to remind ourselves this is about a vulnerable missing child.
“I am a professional police officer and when you get a request to do something about a vulnerable missing child, you should take that request very seriously."
https://www.liverpoolecho.co.uk/news/liverpool-news/top-cop-vows-no-limit-3375735Like Cameron and May Stephenson was open about his opinion, which was that Madeleine was a missing child. The actions planned were for Operation Grange to approach the case " It is to examine the case and seek to determine, (as if the abduction occurred in the UK) what additional, new investigative approaches we would take and which can assist the Portuguese authorities in progressing the matter."
Although Op Grange was looking for new investigative approaches, the mention of the abduction suggests that any new approaches will be related to that scenario.
So the three people who instigated and organised the involvement of the Met seemed to agree on what crime was committed before any work began.