I find that there was another 'Mavourneen' (Florex, 1913), deep pink, which was a sport of 'Pink Killarney'. See periodical American Florist for March 22, 1913, p. 480, for description. Confusion with this must be the source of the error that Dickson's 1895 'Mavourneen' was a sport of the later 'Killarney'.
While I was muddling around trying to work out how to make my way around the Biodiversity Heritage Library, Jedmar has so efficiently added it. Thank you Brent (and Jedmar). I have a particular interest in the Killarney clan trying to find an identity for "Ruth Spencer’s Chowerup Pink HT".
This conversation reminded me that I'd previously seen a photo of 'Mavourneen' in an old Australian newspaper. Photographs of a specimen bloom and the bush are now added.