Hello just a quick question

I live in the uk and recently it has been ridiculously hot and my 6 week old would not take more than 30ml of a warm bottle. One day we were at my inlaws and when we got out we always carry sma ready made formula and my fiancé gave our little one a bottle of formula without warming so it was chilled. This was the first time our son drank his whole bottle since the heatwave came and I want to know if this is allowed and will it harm my baby or if this is ok?