It would seem that the English translators did have a copy of the French black-and-white book edition and did use some passages from it when translating the English colour version.
It's interesting to note the difference, but it's open to speculation what produced the changes.
While you still appear to cleave to your belief that nothing pleased the translators than to make arbitrary changes to the text, or to command the studios to give then a map with a different route, at least some of the same
information is available in the English version to be found in the Eagle
There is no
mention of Alembick having been discovered "after the theft of the sceptre" in that version, but it is
stated that the photo of the twins was "seized at Müsstler's".
So it while it could
be that LL-C & MT went back to the black-and-white album, there's also the possibility that there was reference to the Eagle
It could also be that there is an urtext, prepared by the Studios for use in translating the Casterman-supplied text used by Eagle
, and supplied to LL-C & MT in turn. This has the additional advantage of presumably being a complete text: the Eagle
, in running the story in an oddly-proportioned landscape format across two pages, but only two tiers of frames high, dropped some frames, meaning that their's was an incomplete version. As both the later translators were perfectly capable of dealing with the French text, it would seem unlikely that they would feel the need to resort to re-drafting an older, partial, English text.
It may be even easier to explain by positing that the alteration was made by Hergé in discussion with the Methuen team; it would seem characteristic of Michael Turner's nature to enquire where the picture of the Alembicks came from.
But this is only speculation...
So, while this is a good catch, like the recent mention
of the change of reason for Alembick's visit to Syldavia, this definitely adds to the richness of the history of the story, but I think we need to have more information before attributing reasons for how it came about.