Hargreaves99 - it is a valid technique only as far as getting away from IVRS is concerned and is no more efficient or effective than either just pulling power or just putting the nose forward a bit to gain speed.
If you remove either the low speed or RoD from the VRS equation then you won't go from IVRS to VRS and any sensible action is likely to achieve that.
Vuichard's 'technique' takes the RoD out by pulling max power - the rest of the manoeuvre , rolling and yawing isn't necessary.
It works for early IVRS only and will not save you from full VRS.
That's why the CAA think it shouldn't be taught.