My little darling took a bottle of expressed/formula milk now and again if I wanted a couple of hours to myself until he was about 4 months old. Then, he starting screaming at the sight of a bottle and wouldnt take anything but the breast.
To ensure I was ready to go back to work (12 months), from about 6-7 months, I started to try and drop feeds by extending the time between the morning feed and the next feed by as long as I could. So, 8am, 12pm, 4pm, 8pm (for example) became, 8am, 1pm, 4pm, 8pm then 8am, 230pm, 4pm 8pm etc. until the one before 4pm disappeared. Then I extended by time between 8am and 4pm to 8am and 6 pm, 8pm. So, by 9 months, he was having 8am, milk/water/juice in cup/finger foods/purees etc all day and then a feed at 6pm. I did not have to upset him and it was a very natural slow, although well planned, transition.
Good luck!! Some breast fed babies just end up hating the bottle, some never like it. We tried many different teats/milks also. He saw the bottle, and screamed before it even got to his mouth!!!!!!
If you think the above option is a good idea, you end up with all day to get about and are needed as a mum at night feeds only. This made my life very manageable. I wish you look in your quest for a happy baby and happy, working mum!