The UK press appear to have some information, although whether this has been officially "leaked" or is based on their own journalism I leave you to judge. Unless as at least one story suggested we had updated the US authorities and the "leak" was there.

Anyway amidst the reporting is this gem about the second Novichok use, with my emphasis:
A bottle found at the home of Charlie Rowley, who along with his partner Dawn Sturgess, was poisoned by the nerve agent used in the Skripal attack at the end of last month, is said to have yielded forensic evidence which has also helped drive the investigation. Ms Sturgess subsequently died on 8 July: an inquest into her death was opened and adjourned today with police enquiries continuing. Mr Rowley remains severely ill. His brother, Matthew, has said that Ms Sturgess had sprayed from a discarded perfume bottle the couple had found onto her wrist.
Link:https://www.independent.co.uk/news/u...-a8454501.html

The Daily Mail has slightly more, including a link to a CNN story.
Link:http://www.dailymail.co.uk/news/arti...k-mission.html