@RoryAlsop - Science of music: The Soprano range is between C4 (middle C) and C6 (high C) https://en.wikipedia.org/wiki/Voice_type.
This is an example of C6 (In The End).
The only performance I could find (of immortal Emmerich Kálmán “Die Csárdásfürstin”) where she takes C6 (all others take C5) https://youtu.be/jeFTpIPMTLk?t=299