Reported by Stuart McFarlane in a fb post:
“If anyone else wants to use their C64 Mini on a real CRT TV then I can highly recommend this little bit of kit, it converts the HDMI signal into PAL/NTSC Composite and dual mono audio channels, the picture quality is incredible. I've been using it for a few days now and I love it. :D”
Black HDMI to RCA Composite Video Audio AV CVBS Adapter Converter FT