Complex sentence: Jamelia and Finnigan always appear in seat 3, whilst Sawalha moves to seat 4 when she appears alongside Jamelia and to seat 2 when she appears alongside Finnigan and any two of Street-Porter, Moore or Hewson.
Split into simpler sentences: Jamelia and Finnigan always appear in seat 3, whilst Sawalha moves to seat 2 when she appears alongside Finnigan and to seat 4 when she appears alongside Jamelia. Sawalha also moves to seat 2 when she appear alongside any two of Street-Porter, Moore or Hewson.