Hi Tegan
My little man was born a little after your little Charlie and I use something my mum used and my nanny used too!!.... Gripe water!
I use Corams Alcohol free gripe water... No artificial sweetners, colourant free, the ingrediants are - Dill seed oil, caraway oil, cinnamon bark oil, clove bud oil, cardamom oil and it contains a little bit of sucrose...
I find this to be a great help in getting those stubborn poos out!
The whole point of the stuff is for wind pain but it really helps get the poos out too.

Good luck