OK I have further updates to share!
The standard 32GB memory card is only good for approx. 2 to 3 hours of recording.
This varies depending on how much time is spent driving, and how much time you spend parked up.
I guess in most cases you probably only need up to a few hours of footage anyway - if anything significant happens you are going to download the video fairly quickly.
I bought a 256GB sd card for $79 from JBhifi - so I think this will cover me for a week of driving, which is plenty!
When parked up (which means ignition off), then the unit goes into "parking mode" and drops the frame rate to 1 per second, unless movement is detected, or the integrated gyro sensor detects anything - in which case the normal frame rate is used for a user definable period of time (1 second to 30 seconds - I picked 10) - which means you can record a lot of video when parked for minimum storage space.
I think most users will configure their units to record all the time, or until the unit detects the battery voltage has dropped to 11.7 or 12v (you can decide).
If you view the footage later, it will let you know which parts contain "motion" detected or an "impact" detected.
You can configure the unit to shutdown automatically when you are parked, the options are after 1 minute, 3 hours (odd that there is nothing between this range), or there are higher timed options such as 6, 12, 24hours etc - or to never power off. This covers time parked when at work/shopping etc - and you can choose to manually turn it off when you are parked at home if you wanted, just press and hold the power button - but it can serve as some additional home security if you left it running until the battery level drops.
I am still searching for a more technical user discussion forum - no joy as yet.