Can you please confirm that _Off to Sea Once More_ was 1956? I ask just for my own info. Someday I'd like to arrange the recorded chanties on a timeline. I'm particularly interested in the issue of interaction between Hugill and Lloyd/MacColl/others.
"Stormalong" seems intriguing in this regard. It is quite a distinct version of the song that MacColl is singing -- one which I don't recall seeing anywhere before Hugill. Some of the historical references to "Stormalong" by title alone might be referring to this version. And some of the song texts without tune could be, though I cannot really get them to scan. Hugill published it in 1961, saying he'd got it from Harding the Barbadian.
The question then would be, where did MacColl get it? His matches Hugill's quite well. The most likely answer is that MacColl learned it personally from Hugill by 1956. One supposes Hugill sang it for him, perhaps emphasizing the vocal "breaks" that characterize MacColl performance and which Hugill notes in SfSS directly before the song. This would be interesting though because I'm not sure Hugill was ever known to perform this song later on; indeed, he seemed to avoid chanties that required a "bluesy" expression.
The other possibility, that Hugill learned it from MacColl, seems too bizarre to consider. What isn't so far fetched though is if Hugill taught it to MacColl, MacColl put his own spin on it, and then that interpretation had some influence on Hugill's published version.
In any case, this seems to be evidence that Hugill and MacColl (and maybe Lloyd) had interacted in the '50s. Unless I am missing something.