U could try some of the sites mentioned above to buy a recording Foe. I'm afraid I learn by ear so cant supplie NE form of written music. Sorry not to be more help.
Last Saturday I actually Compleated the first installment of my attempt to do all the walks mentioned in the song! (my original reason for requesting the lyrics, though I've ended up singing it too)
I started with verse 6 as It's the shortest of all the walks & I cant do it in order as Litton Cheney Youth hostel (1/2way on 1st walk) Has closed for winter :( So I thought I'd be sensibe & build up gently... Even If you wouldn't describe some of the Puyrbec hills as Gentle!