Unfortunately, according to an article I read, after The Savoy Hotel underwent a major refurbishment in 2010, the hotel looks little like it did many decades earlier and I’m guessing the plaque is gone. Here is the excerpt of the article that mentions this and the link to the article itself. And I’m including excerpts and a link to another article that also tells the story of a woman who thought she could sense ghosts going to The Savoy Hotel and seeing the plaque.
In addition another “Savoy client” was Charles Frohman and when in London ate every day at the Savoy Grill and was within easy walking distance of the Theatres he ran in London. Frohman did not stay in the main Savoy hotel but at no. 81 Savoy court. This was a serviced apartment block built by the Savoy as part of the development of the Strand side of the hotel in 1904. These were the first serviced apartments in Britain with access to the hotel’s facilities. No.81 comprised a sitting room, bathroom and bedroom on the sixth floor of the court. After Frohman’s death a wreath was placed on the chair of his regular table in the Savoy Grill in 1922 on the anniversary of his death. The card read “to the memory of Charles Frohman, placed here in his seat by a few British and American friends. Why fear death? Death is only a beautiful adventure”.
The card bore the date 7 May, 1922. There was a tradition in the Grill of leaving a regular client’s table empty on the day that his death was announced, but evidently Frohman’s fans ensure that on the day of his death that his table was kept empty for many years after. On a nearby pillar in the Grill was a small brass plaque, it was inscribed: “This table was regularly used by Charles Frohman for many years up to 1915.”
In October 2010 the Savoy Hotel underwent a multi-million pound refurbishment, little now remains of the hotel that was once frequented by Frohman and Kessler.
https://www.garemaritime.com/the-champagne-king-the-playwright-and-the-savoy-hotel/
A third story involves a lady named Joan Grant who regarded herself as a “sensitive” with the ability to “see” the departed spirits of the dead, and who, with her husband Charles was dining at the grill room of The Savoy Hotel in London, towards the end of the Second World War, in 1944.
Having been shown to an empty table, and seated with her back to a square pillar, Mrs. Grant became disturbed because she sensed the presence of a disembodied spirit in the chair. The Titanic Commutator, a publication of the Titanic Historical Society, continues the story:
Joan Grant then decided to help the lone spirit and:
…offered thoughts of affection and kindness to the ghost until his loneliness was dissipated.
Several departed friends of the spirit apparently then appeared and helped him to leave his earthly prison. The report concluded:
After the Grants had finished their dinner and arose to leave, Joan noticed a small brass plaque affixed to the column behind her chair. It read:
“This Table was Regularly Used by Charles Frohman for Many Years up to 1915.”
Frohman had been a regular customer of The Savoy Hotel for many years before his death on the Lusitania and he usually sat in the same place in the same chair, often discussing designs for theatrical sets with the famous writer of children’s books, J.M. Barrie, whose plays Frohman featured in his theatres both in America and Great Britain.
https://www.rmslusitania.info/people/saloon/charles-frohman/