Ok so to conclude this thread here are some observations on the above experiment.
These were my neighbours plants, started from clones and grew outdoors
in soil and fabric bags. They started to develop PWD late August after a 7 day stretch of humid and hot weather.
After using treatment described in posts above I noticed the sun dried the milk to a clear, glossy coating with that distinctive “baby smell”, Anyone with kids will attest to this.
It is this slippery coating along with a brief time where the sun interacts with the milk proteins to form a antiseptic effect. This makes it hard for the spores to land and take hold afterward. I am not a botanist so this is purely conjecture based on constant scrutiny the last week.
The leaves that were infected did yellow up quickly and were easier to identify and remove.
The weather has been humid and rainy but plants are now thriving and stacking buds like crazy. Fingers crossed.
Thanks all for your replies, advice and remedies.
Sparky