@marksemczyszyn Yes, I believe he did, though I can't find that exact reference (though I seem to remember reading that somewhere too). Jez certainly helped Bell and Braben get to grips with the Commodore 64, see here:

https://www.timeextension.com/features/jez-san-on-argonaut-star-fox-and-working-with-nintendo

He was also responsible for the PDS system that they used to connect the BBC Micro dev system to the Commodore 64, and he is credited in the source code for converting Julie Dunn's music driver to the Beeb:

https://elite.bbcelite.com/c64/main/subroutine/bdirqhere.html

Sounds like he was pretty essential!