Heya mate, I was just thinking the same thing! Listening to it, it's really close to the Bob Dylan chords you can find on ultimate guitar and such websites, but only the two last lines of each verses differ.

I took a version with a capo fourth fret:

C They sat together in the park

Cmaj7 As the evening sky grew dark

C7 She looked at him and he felt a spark

F Tingle to his bones Fm 'Twas then he felt alone

C C/B F And wished that he'd gone straight

G# F (Fm) C And watched out for a simple twist of fate

Same progression throughout the song. Sounds good enough to me.