I used breastmilk once, then formula but when I eweaned her properly I didn't bother with baby rice as she was 51/2 months and we used the baby led weaning approach.
Is Finlay used to taking formula, it tastes very different to breastmilk so if he's not used to it he may not like it.
By the way he is the most gorgeous baby ever, I love your avator it makes me smile.