Gibb, somebody around here must know if Hugill and Lloyd were in contact before 1956. I think your skepticism overall is well grounded, and I do agree that, yes, Lloyd may have been responsible for the "blood-red." The evidence isn't conclusive in either direction. And if experience is any indicator, the likelihood that the mystery will be solved is remote.

I met Hugill on two occasions, once in 1988. At that time he expressed his opinion that Lloyd's versions of sea songs ("Farewell, My Dearest Nancy" in particular) were not always quite authentic.

Perhaps Hugill saw "Moby Dick" (it's hard to imagine that he didn't!) and, if he didn't know Lloyd at the time, simply assumed that "Blood-Red" Roses was the "Yank" version!

Hugill was indeed the last and greatest living authority on sea shanties, but some of his statements were apparently hasty. He wrote for a popular rather than a scholarly audience, and while he certainly did try to get things right, he wasn't always sufficiently critical of secondary sources.

"Overlooked by most collectors" is strictly true, though it tells us nothing about the song's popularity. Doerflinger included it (through Silsbee), but it's absent from other important collections like those of Whall, Bullen, Robinson, King, Colcord, C. F. Smith, and Sampson. As I've said, Carpenter and Gordon don't seem to have collected it either.

Hugill's statement that the song itself (however red the roses may have been) was "popular among Liverpool seamen" is evidence (though not proof) because was a Liverpool man himself and in a position to know. OTOH, he may simply have been told by a shipmate, "Sure, we all knew that one!" We don't know. We probably never will. And it may not make much difference.