Hi Petr,
Just giving you an update to your original post - as far as I can tell with the Anniversary Update - the problem wouldn't of been detected anyway as all builds on Microsoft's end were pretty much stable. Since Windows 10 RTM'd last year, every update in the Insider Channel did the updates flawlessly. Even after I got 14393 (the RTM of the Anniversary update) Avast was running fine (this was roughly 2 weeks ago).
It wasn't until I saw Avast had been updated that I started to get the BSODs, and knew straight away there was something with the update that was the problem. The problem was, I couldn't log anything in Windows as it would reset to the last known good configuration, and I couldnt even get into Windows in Safe Mode.
Anyway, I dunno how you guys and girls found the problem, but im glad you all did and more than anything, glad that its been fixed with minimal effect on other people. Well done to everyone involved.
Also thank you to the kind gentleman who helped me out with getting my system back to working order. (Forget his name, its buried in the posts now)