I suggest you read through this thread again and, on the important points, you should find the clarification you seek. If still in doubt you might refer again to the parallel discussion at TMP where the reliability of those authors (et al)and the sources references they cite, has also been analysed quite thoroughly. I believe the question to which you refer was put to Susan Howard, but in answer to your query: yes.
Did you not post this statement regarding Elizabeth Sparrow’s work?
For what seems to be a thorough investigation of the subject of the British intelligence effort and support for French opponents to the Republican and Imperial regimes, I recommend Elizabeth Sparrow, Secret Service: British Agents in France, 1792–1815, which I have just found. Detailed footnotes at the bottom of each page. No mention of guerrilla training camps.
Your wording indicates that you have not read the work, and if you do you’ll find that Sparrow implicates Pitt in the conspiracy against Napoleon, along with the Royal Navy and the British intelligence service, along with funding for the Bourbons and their misadventures.
Have you read Sparrow’ work now, along with the other five that I posted and referred to and, most importantly, the primary source references that they used? If you haven’t, then a well-reasoned refutation of those authors, including Sparrow’s, contentions cannot be made.
As for the TMP thread, those who disagree have the same difficulties with sourcing that you appear to have. They also tend to engage in ad hominem comments, personal degradation of those with whom they disagree, along with historical bias against the French and Napoleon.
I submit that if the discussion were reversed, and credible secondary authors were accusing Napoleon and his security services with murder plots against the Bourbons and the British government, you and others would be more than happy to agree with them.