Yes and yes. I'll put it in laymen's terms for you - they have a strong idea who it is, how it was done and why, but that's not for public disclosure.
Firstly, on the most simple level the judicial process requires limited public disclosure to allow a fair investigation and any trial to be impartial.
Secondly, disclosure of information into the public realm may weaken the investigatory process, which can further lead to complications at trial.
As such, there are investigatory procedures that they're clearly and rightly following, however I doubt you have experience of them from all this.
With regards to the nerve agent's application, all the above applies alongside being exempt of FOI and also under the overall OSA umbrella.
There are things that people know, including the press, that they simply shouldn't and cannot be said and that's the nature of the beast.
I'm sure there's a fair few (ex)service or emergency-service individuals on here who know information which simply isn't allowed in the public realm.
So back to laymen's terms: there will be evidence, which the FCO, NATO and other powers will have been disclosed to, but not to the public.
OPCW are on their way so hopefully their objective assessment of the compound may help provide further 'evidence' of culpability.
'They have a strong idea who it is? Have they? They have a strong idea how it was done and why? Have they? According to your good self they have. You are using assumptions unless you are privy to information that is not in the public domain, that is.
I'l repeat, there is no credible evidence that has been presented to indicate that Putin gave the orders for this incident. It is all conjecture and assumptions.
To quote your good self,
"I feel that a wave of support for these false-flag, anti-government mentalities has a huge part to play in while people are doubting the validity.
In no way am I saying the government is perfect and I do appreciate that their view of the truth is often somewhat jaded, but it's become absurd.
If growing swathes of the populous think the world is bloody flat, then believing that this is some form of Brexit conspiracy is for them small-fries.
Only last week, I had someone claiming that the BBC was untrustworthy because it was manipulated by the government, so they used RT instead.
The irony of it all simply went over his head! Often, the simplest and most logical argument is the correct one - it's not all bloody perverse".
Dismissing 'false flag' that leads to 'doubting the validity' was the exact same bull put around about weapons of mass destruction. Anyone, including Corbyn, that didn't say, 'Saddam has weapons of mass destruction and they will come and wipe out the UK in 45 minutes' were deemed to be using a 'false flag to question the validity'. Unfortunately for millions of Iriaqi's the validity was all to real.
The government's (their) 'view of the truth is somewhat jaded' is an understatement in the extreme. It is hardly absurd to question the government and what it is saying as it was with WMD. It is absurd not to question what the government are saying. As it is absurd not to question the government about their handouts from Russian oligarchs. But the likes of Johnson want to close that issue down because it is uncomfortable for them.
'Often the simplest and most logical argument is the correct one'. Yes it is. There is no evidence Putin is guilty and anyone who says otherwise is 'bloody perverse'.
The OPCW need to be on their way to a number of places including Porton Down and to the US and Israel and all those that have not sign the chemical treaty. The OPCW need to question the Russian scientist who wrote a book about making it to find out if he has been active again. But that would be absurd to mention that. Because? It was Putin and everyone and their dog knows it.