You are quite right that I am lacking complete awareness, so I think it would behoove the author to at least link to something to back up their statement, and without sourcing it does feel like spin.
Similarly, there's a section of the article where the author suggests D-notices were used to suppress a link between Sergei Skripal's alleged handler and the Orbis Intelligence company whose founder wrote the dossier. There is again no souring or backing up this allegation. I didn't understand here either, why the author is using these unsourced points to discuss D Notices