So, having only used Visual Studio a little and not extensively, while doing my third C# studies and more of a refresher than a study, I came across something I overlooked - though I had wondered of it - the Local Help Documentation…
On the Menu bar, click Help > Add and Remove Help Content…
Add whatever you need, say C# here… and then after clicking Update, close that window and click Help again and this time select Set Help Preference > Launch in Help Viewer…
And viola, you can see all help documentation offline, and with a lot more useful examples than those available online, though the new docs.microsoft.com might be an improvement now… [Link in above post]
I hope that helps someone…