My pleasuse RD - our thanks to Richard Wastling for the Youtube link. That C shape shoved up to the 3rd fret is also a feature of Paul Simon's "Kathy's Song" and what gives it it's very distinctive flavour; which came 1st I wonder?

You're right about his use of unexpected chords - part of what makes him so special. It's taken for granted now, but who else would have come up with the (very simple but effective) chords for Tambourine Man....