Yes, I can confirm the existence of Les Barkers book, as I do have a copy of that, as well as two old copies of the Penguin book (browning well!). I will look forward to getting a copy of the updated notes (The interesting bit!). I think most of the songs in the book are now very well known, it was an excellent selection.

Incidentally, the penguin is (presumably) one of the few birds with a Welsh name - meaning white head. Named by an early explorer, I believe.