I've just read through this whole thread -and learnt so much -as I'm fairly new to folk.
I'm going to do this at our Folk Club having learnt it from the jazzy/bluesy version. I like to try and understand what I'm singing. (I have nothing 'industrial' in my background) I agree with the theory that both mentions of 'spring' are the season of the year; 'smelled the spring on the smoky wind' being ironic and 'Spring's a girl..' meaning there may not be the sweet smell of blossom in the town but there is still your sweetheart to meet 'in the street at night'. And if I'm wrong -well no one will know -except you mudcatters!

Cheers
Paul B