Resolve 17 New 3D Keyer - Despill makes no difference

For a recent project I shot a presenter on a green screen which I removed and replaced with a still image background.
Took a while but got a pretty good key from a well lit green screen.
Was reading the notes and watching videos about the new 3D Keyer on the edit page and thought I would try it out as it looked so easy.
My subject in the video had dark blonde hair and picks up a bit of green so in Fusion it took a bit of work to isolate, but having seen the results on YouTube of how effective the Despill button has I thought I'd give it a try as a test.
Pressing the Despill button has made absolutely no difference whatsoever. None.
I didn't really expect a total 100% solution but got nothing at all.
Can this possibly be because I am still using the free version of the program ?

DeKeyer settings.png (62.76 KiB) Viewed 1961 times

Original.png (183.63 KiB) Viewed 1961 times

DeSpill.png (252.72 KiB) Viewed 1961 times

It works for me, I am using the free version.

Without despill


With despill

Well that's surprising and unexpected.
Cannot see what's going on here.
I keep trying and the despill refuses to make any difference at all.
Your result looks really good - so I am really frustrated.
May post an official enquiry to the BlackMagic support team.
Thanks for your time and contribution.

BlackMagic have still not got back to me with a response to my question re the DeSpill control so I'll just open it up to the forum again ... Anyone had this problem and know a fix ??