> I was usually told he was widely regarded to hold a grudge against her for some reason no-one really understood.
Who told you that?
For an independent (of Swade) analysis you might like to read Bruce Collier's 1970 PhD thesis (http://robroy.dyndns.info/collier/index.html). This was written well before Swade was on the Babbage case and was based on reading of the primary documents. A couple of quotes from it:
"In the summer of 1843, Menabrea's paper was translated by Ada Augusta, Countess of Lovelace, and only legitimate daughter of Lord Bryon; she composed, in extensive consultation with Babbage, a series of long notes to the paper, which together comprised about three times the length of Menabrea's original version. The whole was published in Richard Taylor's Scientific Memoirs for 1843, 92 under the title "Sketch of the Analytical Engine invented by Charles Babbage, Esq;" this was the only extensive paper on the Analytical Engine published in English during Babbage's life, or, indeed, up to the present. Although it is clear that Lady Lovelace was a woman of considerable interest and talent, and it is clear that she understood to a very considerable degree Babbage's ideas about the general character and significance of the Analytical Engine, and expressed them well in her notes to Menabrea's paper, it is equally clear that the ideas were indeed Babbage's and not hers; indeed, she never made any claim to the contrary. She made a considerable contribution to publicizing the Analytical Engine, but there is no evidence that she advanced the design or theory of it in anyway. And she did not even express an interest in learning about the machine until January 5, 1841, 93 even as late as June 30, 1843, she apparently knew quite little about the mechanical details of the Engine"
"All of this is said not to belittle Lady Lovelace, but because a very exaggerated view has been formed by some recent writers of the significance of her contribution to the Engine or of her role in Babbage's life."
The citations for those parts are Babbage's personal correspondence with Lovelace that are held by the British Museum.