Bella Cornwell is the daughter of Patty and Roger Cornwell, and the older sister of Izzy Cornwell. In September 2000, Izzy left home to study at Hollyoaks Community College, only keeping in touch with Bella through email.
It would appear that Bella no longer exists, as Izzy later mentioned in Episode 1122 (13th November 2003) that she was the only daughter of her parents.