Where I live, people often opt out from the local hospital. For whatever that reason that is.
If that's the case, even though they are going across trusts, the midwives are fine. It's the patient's choice at the end of the day.
The only problem with choosing a different hospital is, that travel is involved with midwife visits instead of popping locally.
As already pointed out though. People who are pregnant can't stay in close proximity to their actually hospital choices at given times..life goes on. Plus some people have premature births. So at the end of the day this is why you are told as a pregnant woman to keep your pregnancy notes with you at all times. Seems a bit of over kill, but complications can happen and if you need care any nearest hospital will help and that includes delivering babies.
Sarah is probably just being ridiculous because she thought scans and her 'gender' blood test was the most important thing to monitor pregnancy. Absolutely not!