You can find Childe the Hunter in Songs of the West
Folk songs of Devon and Cornwall collected from the mouths of the people
by S. Baring Gould, M.A. H. Fleetwood Sheppard, M.A. and F. W. Bussell, Mus. Doc. D.D.

This page gives the origin of the verse Brennan Moor; http://www.bluegrassmessengers.com/brennan-moor--bidder-devon-c1890-baring-gould.aspx
Brennan Moor - Bidder (Devon) c.1890 Baring-Gould Brennan-Moor (Three ravens they flew over Blackistone) Baring-Gould working notebook 3
Performer: Bidder, Bertha Place: England ; Devon ; Moreton hampstead Collector: Baring-Gould, S. (Sabine), 1834-1924
This version (see text below) was titled Brennan-Moor and collected from Bertha Bidder in Devon (no date given - c.1890) Baring-Gould. One copy was retitled, "The Three Ravens."
More properly it could be titled, "Three Ravens They Flew Over Blackistone."

We climbed Blackingstone Rock one day. The next evening, we were watching the series Cold Feet on television. In the final scene, the camera rose from the actors to reveal the location as the top of Blackingstone Rock. My cousin was a location finder for the production company.