I have a few comments to make here; My opinion based on the data.
Take off roll starts at 50:23 approx
Gets going at 50:28
Takeoff speed starts around 50:33
IAS peaks at about 80 Knots @ 50:42
Pitch is steady through the roll until 50:42
PA is steady from 33-42s as well, with a short dip, typical of a positive pitch up (static port sinking)
Trim is repeatedly pitched down during the acceleration and then pitched up prior to the rapid climb, then trimmed back down again
Full power applied in the time up to 50:28
Distance travelled approx 380m in the 50:25 > 50:42 sec range.
I have flown Dick VanGrunsven's own personal RV12, and even with two of us, (he is very tall & I am errr..more solid) the takeoff distance is half that.
I have made my comments known on this before. There is nothing to suggest this is anything other than the result of deliberate and foolish acts by the pilot.
I might be proven wrong when the NSW police evidence is presented to the coroner. But it looks unlikely.