OK.
Over 10 days have gone past and I have got round to looking at the videos produced by the 512GW which I have attached to the rear screen (this is a second 512GW, not a "rear camera" extension. I now have a 512 GW on both front and back).
The PARKING MODE = OFF.
I have put off checking the parking mode for at least a few weeks.
The G-SENSOR = LO
On this Lo setting I have 90 files on a 64G Card of which 43 are Protected and only 47 are not protected.
This is silly.
There are only the usual road faults (pot-holes, sleeping policemen, etc.) none of which should set the protection.
Both the protected files and other files go back only a couple of days - clearly the protected files (back to file no 369) are not being protected for much longer than the other files (back to file no 383).
This device really needs several more sensitive settings for the G-Sensor lower than the current "LO".
I shall turn it to OFF.
This is the same problem as with the front-facing 512GW when I had 51 protected and 44 normal files.
In the last couple of weeks the year-facing 512GW has overwritten the 64G card more than 5 times without me reformatting it. That is good
because I shall forget or neglect to do it.
There is a fair amount of "shake" on the camera (the front-facing 512GW was the same) and I put that down to the fairly long and 'willowy' mounting arm.
Perhaps things will be better when I use the sticky pad fixing which is much shorter.
Nevertheless, each individual frame is high quality - although it will, no doubt, be better if I can reduce the shake.
It is also difficult to remove the camera without moving the arm at the ball joint (I can't hold the arm still at the same time, because I only have one hand). I might try some glue on the ball to prevent the arm from moving at the ball joint - something like 'pritstick' might be enough and still be "breakable" when I really need to move or remove the ball fitting.
I'm off now to see if the firmware has been updated from 21.6 or the manual updated to reflect changed from before 15.8