For both DS and DD1 I started mixing in 30mls of cows milk with their formula and gradually increasing the ratio of cows milk and decreasing the formula every 3 days till they were 100% on milk (and I'd used up the last of the formula in the tin!!!).

Then I bought DS a fancy new cup which he loved and gave him his milk in that, and he stopped having bottles altogether. DD1, on the other hand, absolutely refuses milk in anything other than a bottle (tried different cups with warm milk, cold milk, flavoured milk - nope) so she still has a bottle of cows milk 2 or 3 times a day because she also refuses to eat dairy (no cheese, yoghurt, butter, nothing). I decided not to stress about the vessel which contains the milk till she's older.

I stopped sterilising at 12 months of age. They both have warm milk first thing in the morning, 180mls each, and last thing before they go to bed because it's part of their bedtime routine. DD1 likes another bottle when she wakes up from her nap but she doesn't nap every day so sometimes has 180mls of milk 3 times a day, sometimes twice. It's just a beverage for them both - they will have breakfast about half an hour after the morning milk, and they have their evening milk after dinner and bath.

I got the 180mls amount from a weaning book I have, it said you shouldn't offer more than that because it will fill them up and then they are less interested in eating and once they are a year old you should really be encouraging their interest in food so they get most of their nutrition from that rather than milk, prior to when their appetite drops at about 18 months, so you aren't in the habit of filling them up on milk (this is where the marketers of toddler formula are very clever, the smaller appetite of a toddler is totally normal because they aren't growing as fast anymore, preying on the natural worries of parents that their children aren't getting enough nutrition).

Thank you to both replies, the part about the milk being a drink rather than a meal makes sense my DS usually had 3 bottles during the day incl his one before bed, but yesterday i gave him 180ml formiula and filled the rest with milk to 240ml, he wasnt interested in his breakfast, he ate lunch but didnt want his middle of the day bottle. He seemed to satisfied alot longer.
Thank you all again
BB