There's a chromatic chord movement in the second half of this song's verse that descends from the iii chord in G (B minor) to the ii chord (A minor) by way of the chord in between (A# minor). Of particular interest here is the melodic sequence of two descending thirds that's sung over the top. The melody starts on D, the third of the B minor chord, then moves down a third to the root, and then another third to the sixth (G). The chord then switches to A# minor and the melodic pattern is repeated: third (C#), root (A#), and sixth (F#). The melody then ends with the final note of the line back up at C natural, the third of A minor.
The only thing that might be considered unusual about this is the sixth, a nonchord tone appearing in what otherwise seems to be a triadic melody. Surely, one of the reasons it's used is that these notes are happening quickly and a bigger melodic jump from the root down to the chord tone, the fifth, would have been awkward. These sixths cannot be accounted for in terms of melodic analysis, though; they are not neighbor tones, escape tones, or passing tones. They are, seemingly, pure color, and their use here by composer Roy Wood is quite remarkable.