Sounds wrong. On a whistle, the cran has the main note broken into parts, just as with a roll, but successive grace notes are always separated by repetitions of the main note.
I think they're pretty similar, but I'm not much of a whistle player -- the main note followed by several descending notes from a higher pitch, back to the main note, which may be repeated.
I've toyed with whistle-style crans on the English, but haven't really worked on them. I understand that what are called "crans" on the anglo are really a very different animal, but I've never tried them, so I have no basis for comment.
Like many things, I think it depends on whom you ask. I Googled "whistle crans" and the first hit was to a whistle tutorial that illustrated crans (via a video clip) without the repetition of the main note. Then I looked at a couple of other sites that described crans as repetitions of the main note interrupted by cuts. The latter seems more uillieann pipe-like to me, and more interesting than the simpler approach. But really, aren't whistle crans better topic for Chiff & Fipple
Getting back to Anglo concertina ...
You seem to be saying that the grace notes follow one another, without the base note in between. ... Is that what's called a "cran" on the anglo?
Yes, at least that's how I was taught. I have a handout from Micheal O Raghallaigh's 2005 class at East Durham, and it lists 9 possible crans. In abc notation, the first cran, on D, would be represented:
The E cran is:
where the parentheses indicate an optional note. An so on up the scale. Except for the three highest crans, all of the notes between the "bookend" main notes are descending. The highest cran is
Because all of the notes of the cran are played in the same bellows direction (depending on whether the main note is press or draw), you could
, I suppose, try to keep the main note going through the cran, but I just tried that and it drowned out everything else. And I don't think it would be possible for mere mortals to play fast enough to repeat the main note between the higher notes, e.g., DdDBDAD, in the time usually allotted.
I believe Noel Hill taught the same D cran, but I don't have any notes on that, and I don't recall him teaching us any other crans.