I just buy COYO Organic coconut yoghurt

Good luck with that one! Is bub allergic to all those?! But I see someone has actually posted a recipe for you

I use 2 cans of coconut milk warmed to body temperature and then mixed with 4 capsules of Inner Health plus. Keep in a warm place (oven or esky) wrapped in a warm jumper for 14 – 16 hours (depends on the temperature outside). Refrigerate for 8 hours before digging in. The water layer often separates out at the bottom but a quick stir before use usually resolves the issue.

Rice milk lacks the fat and protein to make a nice thick yogurt in my experience.