I wasn't very impressed with the first episode but think it developed very well.
I recall a documentary in which an Irish lady, keen on history, starting looking at the birth, death, and burial records of a convent and found that the numbers didn't tally. Eventually, some of the grounds were excavated and many bodies of babies and young children were found. Long Lost Family has also referred to the number of babies who had been found to have been taken from their mothers and given to adoptive parents. Their birth certificates were falsified, in that the adoptive parents' names were recorded, but not the birth parent/s. That was a deliberate, and absolutely, illegal act.
So the Woman in the Wall wasn't so far from reality.