I just stumbled across this not in Ammon WIrgley's Those Were The Days on page 109:

"Joe (Wrigley) sang the "Grenfilt Fox Hunt" and it was the first time I heard it. It tells how three good "owd chums" went to a fox hunt with picks and spades and a bottle of rum.

    "From the Isle of Skye to Laddy Rocks
      They tried in vain to catch this fox,
      With picks and spades and a pair of blocks
      Chance it need drawing.
            Ri tiddy fa laro laddie O
            Ri tiddy fa laro li do"

"It is many years since that famous fox hunt took place, and the hunters are gone to their long rest and no one knows who wrote that once popular local song."

Laddie Rocks seems to be referring to Laddow Rocks just East of Chew Reservoir.

I'm still none the wiser regarding the melody though