Complex sentence: Mrs Thompson's room is noted as being at "the top" of Warley geographically, and higher up socially than he has previously experienced, and serves as a metaphor for Lampton's ambition to rise in the world.
Split into simpler sentences: Mrs Thompson's room is noted as being at "the top" of Warley geographically, and higher up socially than he has previously experienced. It also serves as a metaphor for Lampton's ambition to rise in the world.