fragrance Ann Oldham is Lily of the Valley by Yardley

Actresses and actors not unfrequently wear perfume to get into character. In the highly popular TV series Downton Abbey, The vanity table of Lady Mary - the most seductive of the three Crawley sisters - displays a constant array of fragrance bottles in which she would have decanted her favorite perfumes as was the custom of the day. In the last episode of Season 2, in the Christmas special, a packaged perfume by Guerlain is offered to Isobel as a discreet dramatic prop to help us relive the era. Given the fact that quite a bit of historical research goes into the series, we will assume it's more of a prop than a plain product placement. Your first thought when seeing it is "Aha, Mitsouko ca. 1919!"...

As the series thinks very much in terms of societal turning points, Mitsouko would represent well the new opening decade of the 1920s.
But best of all, we are told that the cast actually does wear perfume to get into character. So what perfume should you spray in the air to smell a bit like Downton Abbey (while waiting for the signature fragrances inspired by the characters?)
One of the names that was released by make-up artist Ann Oldham is Lily of the Valley by Yardley. Launched in 1981, it is completely ahistorical a reference if you think about it in a chronological way. If you realize however that the fragrance attempts to reflect the social sanction of good taste of the era, it sounds more judicious.
Light and fresh soliflores would have been considered the sort of scents that a well-bred woman could wear to distinguish her from the trollops dabbing on musk and other unseemly violent "odors".
While a lily of the valley fragrance would not have smelled then like it does today given the central reliance on hydroxycitronellal to recreate the aroma of this flower which can only be a figment of the imagination since it cannot be extracted, it would have belonged to the possible repertoire of soliflores. In fact, Floris of Jermyn Street could have been the one creating a taste for it and a wish to wear the scent of lily of the valley as they introduced a composition called "Lily of the Valley" as early as the mid-18th century .
In Paris it is easier to find Lavender by Yardley than the rest of the Yardley soliflores, so we'll go back to more imaginings when the scent alights in Paris, straight from the UK.