You can buy it from Amazon here for £6.29:
Cut and pasted from Amazon:
A beautiful hardback for the price of a paperback. White's Pocket Classics offer the best-loved classics in an irresistible small hardback with original illustrations embossed on the covers and all the features of a fine edition - coloured endpapers, marker ribbon, illustrated title pages and new typesetting - combining the best contemporary design with the luxury of a hardback and introductions by today’s popular authors, to make the most appealing classics available at a paperback price and a perfect gift. This edition of Sherlock Holmes' greatest cases uniquely combines Holmes' most famous case, The Hound of the Baskervilles, with Arthur Conan Doyle's own twelve favourite Sherlock Holmes stories.
This is way better than the Mark Gatiss book! (sorry Mark).