Complex sentence: She remained with The Royal Ballet for her whole career but she did perform as a guest artist with many leading ballet companies around the world and, since retiring from ballet in 2007, has continued to be very active in the world of dance.
Split into simpler sentences: She remained with The Royal Ballet for her whole career but she did perform as a guest artist with many leading ballet companies around the world. Since retiring from ballet in 2007, Bussell has continued to be very committed to the world of dance.