British Actor Arthur Wontner played Sherlock Holmes in movies from 1931-1937. Here is what I believe is the latest information on the 5 films.
The movies are:
The Sleeping Cardinal (1931) (USA title: Sherlock Holmes' Fatal Hour), based on Doyle's two stories, "The Final Problem" and "The Adventure of the Empty House"
(Lost) The Missing Rembrandt (1932) based on "The Adventure of Charles Augustus Milverton
The Sign of Four: Sherlock Holmes' Greatest Case (1932)
The Triumph of Sherlock Holmes (1935), based on The Valley of Fear
Silver Blaze (1937) (USA title: Murder at the Baskervilles, release 1941), based on "The Adventure of Silver Blaze"
All the movies except The Missing Rembrandt are readily available for free viewing on the internet. The Missing Rembrandt is still considered a lost film.
The films are also available in various DVD compilations over the years. Unfortunately the quality of the picture and sound is usually quite poor.
The British Film Institute (BFI) holds 35mm prints on the 4 surviving films. Only 1 has been released in good quality.
The Sign of Four : Sherlock Holmes Greatest Case(1932) was put out on the Ealing Studios Rarities Collection: Volume 14 [DVD]. The B/W version is 74 mins / 1.33:1 / Mono / English.
Ealing Studios, West London, made more than 150 films over a three decade period. The Sign of Four was the only Arthur Wontner movie made at that studio.
In August, 2019, a distinguished groups of film historians, screenwriters and Sherlock Holmes film experts formed a committee to find and restore early silent and sound Sherlock movies.
The group is called, Searching for Sherlock: The Game’s Afoot. This includes finding the lost The Missing Rembrandt and hopefully releasing excellent quality copies of the other 3 Arthur Wontner films.
The current Covid-19 pandemic has slowed the work of this group.
I am hopeful that one day all 5 Arthur Wontner Sherlock Holmes movies will be released for the public to enjoy.