[2020] Putting a leash on Steam - no I don't want to update a mess my campaign up.

GKPecap said: Was thinking also if you toggle to update only on launch and then launch off-line, then go on-line that should hold the game in current version also?

No, Steam will apply the latest version automatically. Use the technique that @ThatDaniel mentioned instead.

GKPecap said: Can't believe that making updates optional and user driven could be that hard.

Steam do not provide such a facility I'm afraid. Their only choice is to update immediately or when you next play.  

Yes, Steam updates mods automatically too.

Most likely the mods you are using are not updated to work with 2.8 yet.  

GKPecap said: Now I can load the game without mods, but it gets stuck with them at 30%, and they are all updated and in correct load order too.

Can you pin it down to any particular mod by a process of elimination?