JJHere nigel simplifies the harmony by ‘ignoring’ some of the changes. ignore the chord changes in bars 19 and 21 and you’ll end up with a very similar sound. so think dm for two bars and am for two bars. The first chord melody moment of the solo. nigel is aware of the chord changes and he chooses unusual chord shapes to bring out interesting melodies.
JOn the third chorus nigel wants to change up a gear again. He starts already on fire with a series of quartal voicings played melodically. Quartal voicings are chords built using perfect or augmented 4ths (eg C-F-B). The gear change is also reflected in the speed that goes up a notch with the phrases built in triplets.