Darren:
Bourrinet was an ICC member, and that is how the ICC version, which is the original version, came about. Here, written in their inimitable style, is the ICC side of the story of the dispute between Bourrinet over the ICC’s right to continue its distribution:
https://en.internationalism.org/icconline/201502/12079/doctor-bourrinet-fraud-and-self-proclaimed-historian
After leaving the ICC, Bourrinet off-and-on either in French or in English or both, made his constantly revised two books (one about the Dutch; one about the Italians) freely available on his site http://www.left-dis.nl . Presumably he doesn’t anymore now that he has got it commercially published. (Copyright.)
I read the internet ‘middle versions’, but not the ICC version or the Brill version, so, aside from no doubt added information, photos etc, I can’t say what the political differences might be at the two ends. (No doubt ICC member Alf would be pleased to tell us us?)
But more important (and having nothing to do with Bourrinet vs the ICC) is the inaccuracy in the book concerning Mattick and company’s attitude on Spain:
https://increasinglyadequate.com/commleft_german.html . ( Thanks to klas batalo for posting this link already on May 17. )