Sadly, no I don't still have the book - I got it through interlibrary loans. I can imagine it wouldn't have had any more to the quote than what I've already written? Sadly these local folklore books are often not very well referenced and you can't tell where the author found the quote originally (sometimes it's just from the last local folklore book, clearly).

But I can tell you that the Leland quote would have come from his 'Itinerary' of travels around Britain. You just need the right volume. It's not online, but you ought to be able to order it from the library or buy one from (for example) here:
http://www.abebooks.co.uk/servlet/SearchResults?sts=t&an=leland&y=0&tn=itinerary&x=0&sortby=3

Maybe someone more familiar with Cumbria might be able to guess the other sources. It would be cheap enough to buy a copy of Rowling's book, but I'm not sure it would get you anywhere.
http://www.abebooks.co.uk/servlet/SearchResults?sts=t&an=rowling&y=0&kn=folklore+cumbria&x=0&sortby=3