For completeness, now that the auction is over for the possible Boulton & Mills "rose bowl" (ribbed opal body, amber rim and three amber feet), I can confirm that I never had a response to my query about the Id claimed to be as per Cyril Manley's book.
In the book, I can find no examples of bowls that resemble the one in the auction listing. However, on pages 68-69, a bowl is shown with a broad-ribbed opal coloured body for which Manley stated, "... so extravagantly designed, it can only be Boulton & Mills ...". It seems to me that this comment was in respect of the very wide and full folds in the rim, which are about half the height of the overall piece, and include all-over "nodules". This is nothing at all like the Rose Bowl mentioned, which is positively plain in comparison. Manley also added, "This type of design is at times the only way collectors can identify this firm's specimens." There was no comment on the style of ribbed body being an identifier for Boulton & Mills.
The "extravagant" bowl shown in Manley's book has a much paler shade of pink for the interior. Perhaps some of the pinks we see in online images are simply not the true shade? Or perhaps the book colours were not right? I have a bowl, of unknown maker, with pink interior that is between the shades shown in Manley's book and that in the auction listing. Maybe there were various shades of pink between the very pale and the very dark?
Although the auction rose bowl may have been made by Boulton & Mills, without definite proof we should consider that it could have been made by several other firms as well.
That's the trouble with much of the English (and elsewhere) "Victorian" decorative wares ... they often look much the same whoever made them.