All hungry baby milk does say from newborn I agree. But I think it needs to be used cautiously, as it contains the same fat and calories as first milk, but a baby will drink it in less quantity due to the whey:casien ratio, which is more similar to cows milk, so babies find it harder to digest, hence keeping them fuller for longer.
HB milk can commonly cause not so serious problems such as colic and constipation, but there is also a potential risk that a very young baby who needs to feed little and often will end up feeding just little, with long spaces between feeds, so would not be consuming the calories and nutrients they need for healthy growth.
First milk has a closer protein profile to breast milk so it is easier on baby's tummies and should always be the first choice for as long as possible if you are formula feeding.
Obviously Im not gonna say that your HV or doctor are wrong as Im not in the medical profession and dont know your baby's situation or medical history. xxx