AutoGradientRemoval.py script is not listed in get scripts menu

Hi all.
Just watched Rich from Deep Space Astro using the above script (https://www.youtube.com/watch?v=Xdu6nuY3xI0&t=54s) but for the life of me I cannot find it in my get scripts menu. I have even uninstalled & reinstalled the latest version (1.4.4 commit e89421c running Win 10) but nothing. Any ideas please?
Many thanks.
Dave