One source (dated 2004) has an Anne Marina Christine Faggionato, 'marchand de tableaux', married to David Grob. Company records (for 'Art International UK Ltd', based in Monaco, have an Anne Faggionato, of Swiss origin, b. 1955, alongside an Irene Faggionato, of French origin, b. 1929, her mother according to this source-
https://www.leagle.com/decision/infdco20120126860- which also mentions her 'then-husband' David Grob.
The only reason I thought to look into this was because I know that there was a Faggionato/ Abensperg-Traun marriage; Gerard Francois Aristide Faggionato (b. 1960, Italy), a London (formerly of Monaco, which is what leads me to consider a connection exists) art dealer m. 1992, Cecilia Claudine Maria Luise Grafin von Abensperg und Traun, dau. of Graf Ernst Ferdinand Johannes Eustachius Marie von Abensperg und Traun (1935-1994). Not entirely within this group's remit, of course, but this would at least place these Faggionatos in a certain context (being thus related by marriage to the Starhemberg princes and Thun und Hohenstein counts).
Taking this into account, Thomas (son of Anne Faggionato) is, I suggest, the 'Thomas Gilles Grob' who appears in the Times Birth and Christening notices records on ancestry and elsewhere, with his mother's name, Anne Faggionato, being also provided.