So… In preparation for doing what will likely be a 90 second learning video on the header coder in a “typical” ZIL game file I wanted to remind myself how VERSION and STATUS-LINE worked… And wound up recording a 65 min behind the scenes video !!
That said, firstly it was a useful exercise and thought process and it may help others to understand a) how my crazy brain works and b) a bit about ZIL, but also it actually got me 80% there in terms of stripping out the status line and making this something you choose to have (in version 5 of Z machine) rather than have to have it every time. An unexpected benefit of delving into the code!
That and yes, 65 minutes later, I can now record a very short video explaining the header code in ZIL 
Adam