How to wean bottles (9 month old)

My girl has 6 bottles given to her a day (every 3 hours) and drinks about 100ml out of each. She gets 2 solid meals a day and lots of finger foods throughout.

We recently went to the midwife and she told me she should be having 3 or 4 bottles at her age. With more in them.

Some of the mothers in my mothers group are down to 2 or 3 bottles a day.

My baby is tiny (6.5kg or 14lbs) so I don’t even know if she can fit a bigger bottle into her tiny body.

We’ve started trying to get rib of her midnight bottle and have her sleep through the night.

How do I wean some of those bottles?