When does The Adventures of Sherlock Holmes return?

The first two series were shown under the title The Adventures of Sherlock Holmes and subsequent series with the titles of other short story collections by Sir Arthur Conan Doyle. The series was broadcast on the ITV network in the UK and starred Jeremy Brett as Holmes. Dr. Watson was played by David Burke in the first series (Adventures) and by Edward Hardwicke from the second series (Return) onwards.