Interesting 1911 reference from 'The Garden' which reverses the usual parentage of 'Lady Hillingdon':

"In addition to the varieties named we have the parentage given of the following well-known sorts: [...] Lady Hillingdon (Mme. Hoste x Papa Gontier), [...] P."

I don't know who "P." is but he seems to be in the know, and I do wonder if this parentage might be the correct one, rather than 'Papa Gontier' x 'Mme. Hoste'. To me, it makes more sense to have 'Mme. Hoste' as the seed parent, as it was known to set hips very readily. Not only that, but Lowe & Shawyer's other famous rose 'Mrs. George Shawyer', from the same era, had 'Mme. Hoste' as a seed parent.
I think sometimes early breeders would say a new variety was a cross between this and that, perhaps being a bit secretive, and a certain parentage would become writ in stone, so to speak.

I realise that in the Australian book on tea roses the fragrance is described as moderate -- and no doubt that's how it comes across in those climatic conditions. In Europe, however (or at least Britain) Lady Hillingdon's scent is dependably strong (I have grown it for almost a decade). Indeed, it may well be the most strongly scented tea. See David Austin, Peter Beales and Trevor White websites, all describing the scent as 'strong' or the rose as 'very fragrant'. From memory Graham Stuart Thomas also praised the scent. So the description should probably be 'moderate to strong, opinions vary fragrance'.