Thank you for your contributions @beardeddragon1225 and everybody else for your input, I’m pleased to hear that re-pasting solved your issues and it wasn’t something more sinister! Although I’ve been quiet recently I have been keeping an eye on this post every day.
I’m currently working on putting together a "how to improve your performance in Vermintide 2" article but it’s taking longer than I had originally hoped due to the sheer amount of headache-inducing variables involved!
That being said, it’s awfully hard from a support perspective to determine whether a player’s performance drops are caused by something local without having the PC in our hands, or as a result of something we’ve changed. Symptoms vary largely from person to person too. We’re very aware a number of people notice a degradation in performance after large patches, especially so with 1.5. I’m rambling on a bit and thinking out loud here which I appreciate isn’t much help to anybody but please know we’re listening and take your complaints seriously.