Thanks for your comments Max. There are some related videos from the same trip. I enjoyed watching all four skiing - looking down from the lift and also standing on the piste. As you point out the skier was not necessarily demoing.
I still feel I don't quite understand flex to release completely, although a comment you made above did clarify it a bit for me.
So am I right in saying that in a one footed release turn, the first move is the weight shift to the upper ski LTE, then unweight, flex and tip the lower ski , and also that - there should be no extension of the uphill leg at all until on the BTE. It is this last point that I am concerned about. I ask this because I feel at times I am extending the upper leg a bit as I roll from LTE to BTE ie in transition. I am trying to eliminate it completely.
In a two footed release, then ? no extension of either leg between move from uphill edges to downhill edges, and also no leg extension between point of maximum flexion late in the turn until onto the new turn inside edges, ( or, if in the air then with edges rolled to this side.)