Maybe you have another link with objections to his objections?
As such, here are the facts in the Skripal case: https://www.counterterrorism.police.uk/salisbury/
Yeah, but the guy on the linked-to page is not making claims. He's just asking why.
It would be far more useful for you or someone else to provide a link that answered his specific questions in detail rather than give a link to a non-specific information dump that does not specifically address those questions.
An information dump is far more beneficial to the discussion of the case than a discredited former ambassador who tends to side with kleptocratic maniacs in Russia
I don't doubt that the British secret services have adjusted the official story, but the idea that there is something genuinely fishy going on requires real evidence. His waffle-ing about Bellingcat being warmongers (if I recall his wording correctly) is similarly uninspiring.