This reply is three years after your comment but the question is still open so I figure it's okay to re-open the thread.

I got bored and went trawling on the internet for older references to Vibert's 1848 Noisette, Jeanne d'Arc. (and a couple others I thought sounded interesting). I don't think it actually gets us any farther in figuring out the St. Leonard's/Little Mary Tower/Pale Pink Noisette issue. Oh well! It was fun. Here's what I found!

The Rose Manual; containing accurate descriptions of all the finest varieties of roses, properly classes in their respective families, their character and mode of culture, with directions for their propagation, and the destruction of insects. By Buist, Robert, 1805-1880 pub 1851 pg 94 archive.org
“Jeanne d’Arc, a strong grower, of a pure white color, very double, flowers rather small for the habit of the plant.” (In the chapter on Noisettes)

Culture Generale. Etablissement Horticole de Avoux et Crozy. By M. Avoux and M. Crozy (?) pg. 81 pub. 1847 gallic.bnf.fr
“Jeanne d’Arc, moy. Tr. Mult. Ou pj. Blanc, centre legerement carne … 1F50c” (listed under “Rosiers Noisettes”)

The amateur’s guide and flower-garden directory: containing every requisite detail for the successful cultivation of the flower garden. Embracing the classification of the best varieties of roses, and all plants requisite for the garden with directions for propagation, and remedies for the destruction of insects. To which is added the Vegetable garden manual. By Clark, John T. C. pub 1856 archive.org
“Jeannie d’Arc,……. Pure white,… Cupped and very double. Flowers rather small. A strong grower.” (listed under “Rosa Moschata”)

1861 descriptive catalogue of Southern and acclimated fruit trees, evergreens, roses, grape vines, rare trees, shrubs, &c., cultivated and for sale at Pomaria Nurseries. By Pomaria Nurseries, Summer, William, 1815-1878; Henry G. Gilbert Nursery and Seed Trade Catalog Collection archive.org
“Joan of Arc—Pure white, fine pillar rose; cupped” (listed under “Noisette Roses”)