If I have to bottle feed a lamb whose mother still likes it, I leave it with her. It'll soon learn to come for its bottle when you appear, but it's better off belonging to a sheep family still.
Re the udder. I accept the vets view that her udder has gone too far to be saved for milk production in the future. However, see my post again. You can have a ewe with a fairly swollen, not producing milk but intact udder or you can have one with a decaying, stinking, coming off in pieces, fly attracting udder. The former is much preferable and is achieved by continuing to massage and strip.