Yes, that's her. My Mother had no knowledge of this, until I informed her. She still seems to think her Grandfather
Italiano/Carlo/Charles is Mary's father, although we do not know for sure. In the 1911 census she is listed as Maria Riani and indeed married under Riani/Reani as it is spelt on her marriage record. I have attached a page of my g grandfather's identity book which states Rosina aquired Italian citizenship when she married on 20 aug 1900. Yet I cannot find a record for this.
At that time (pre-WWI) a bride would have acquired the citizenship of her husband, However, despite what the identity book says and also what the 1911 census says, they did not marry until 1920.
It may be that Carlo already had a wife and they had to wait until she died in order to marry in church but that's purely speculation.
Due to all the inaccuracies found so far then it's possible Susan's birth was not registered under Riani or Sherlock and she was 'adopted' but again speculation.
Would be worth contacting their local church to see what, if any, baptism records for the children are there.