Hi,

it's generally not recommended that babies be weaned onto a bottle at 12mnths. they need to get extra nutrition from food - not milk or formula. And at some time, they will need to wean from the bottle - which is in itself a painful process. At this age it is more preferable to give milk or water in a cup. It is likely that his behaviour was just a new developmental phase - not really a commentary on the quantity of milk - but it easy to get confused by what they are trying to say or do.
If you don't want him to have the bottle, don't give him the bottle. Offer a cup instead. And the breast, if you want him to breastfeed. At this age they can understand what we are saying - gently but firmly tell him you don't want the biting - it hurts. He is a big boy and knows how breastfeeding works. He will get what he needs! Babies do a lot of things at the breast - pinching, twiddling, hitting, biting etc. Mothers don't have to put up with it - nor do they have to switch to the bottle. A bit of gentle but firm negotiation will preserve breastfeeding and eliminate unwanted behavious