ha. and i found it, just in one hour.
apparently, it's not gerry potterton, but gerald. and he did direct an animated short film about a man named george who decides to get a real star for the top of his christmas tree. and so he goes to look for one and has adventures.
that's all i found. but that's enough.
weirdly, gerald potterton also directed this animated movie called "heavy metal," which i also saw when i was a kid, but probably shouldn't have because it was adult animation with — if i remember correctly — boobs and blood. "heavy metal" is way more famous and its cover has this woman warrior riding a pterodactyl.
but "george and the star" is real, even if imdb doesn't know. i think i need to call my mom and brother tomorrow.
there may not be much about "george and the star" online, but at least now there's one more thing: this.