Whilst I was reading the You Beauty Facebook page I read a post about detanglers and someone recommended My Organics Cosmic Dust, so I bought it. This is easily the best detangler I've found.
It smells lovely, doesn't weigh down his hair and easily detangles. Others we've tried have needed so much product that his hair is wet. My Organics only needs a few sprays, we use between four to six sprays for his whole head. Even when his hair is really matted, the knots are no match for Cosmic Dust. It really is wonderful.
You can get Cosmic dust for $6 to $9 (depending if it's on sale or not) from Chemist Warehouse. At the moment it's on sale for $5.39.
The 120ml bottle lasts us a few months if I'm spraying it on and one month if Eljay is spraying it on, haha.