Yes, absolutely. Sometimes it's beyond anyone's control, for example they do close units when there aren't enough staff, but barring that it's the woman's choice. Likewise women being told there aren't sufficient midwives for a home/water birth; it's the Trust's responsibility to provide one.
Similarly, 111 can't withhold permission for you to go to a specific A&E. It might take longer without a referral, for example, but if you turn up to an (open) emergency department with a broken ankle, they're going to treat you.
I'm not saying anyone shouldn't listen to advice, but ask the reasons. If it impacts you, then fine, but if it's more convenient for the doctors and midwives (or "policy"), that's not your problem.
) and has always wanted to be a big sister. We decided to tell her after the scan because she’d been starting to worry about me being ill for so long, and she’s thrilled. 
I did really like my midwife when I met her at my booking in appointment earlier this week though, and the hospital was really quiet and calm. 
How exciting!