It has taken me some time but I have finished the short piece today
https://interceptor121.com/2018/07/28/panasonic-gh5-settings-for-underwater-video/
In hindsight I now see why people do what they do, don't use LOG and even end up using standard picture profiles...
Now considering that I do not want to buy an external recorder or I should say I do not want to spend the money for the housing I need to figure out what I am going to do myself!!!