Steve Gardham wrote: Chappell is not the most reliable source....

No, he's not, but to give him his due, he produced the first real work of its type; there wasn't much prior work to help him. In a way, he is comparable to Thomas Percy a century before: He gathered up stuff, and sometimes altered it (by converting the modal tunes to strict Ionian and Aeolian). Both Percy and Chappell messed up their sources. On the other hand, Chappell didn't hide and even destroy his sources (as Percy did), and Chappell at least made a relatively consistent sort of modifications. Both had later authors come along to produce corrected copies (Percy by Wheatley and Chappell by Wooldridge), but Wooldridge had a much easier job than Wheatley.

I guess the way I would put it is, I think Percy and Chappell are rather comparable -- but Chappell was doing the best he could and Percy was a hack who, although he got a lot of people interested in old songs, really fouled the waters.