Hello Tim, Bruno Putzeys has left Hypex more than two yers ago, and as far as I know, he is not involved at this time with NCore technology development.
He has since founded a new company, called Purifi:
https://www.purifi-audio.com/
And within Purifi Bruno is developing new class D technology.... No, as far as I know, Putzeys may not be applying GaN transistors in his new design.
Saluti, G.