It is indeed a very fine example of the Mark Titan, and a valuable addition to our list of known examples, which now stands at seven. The serial number is well below the other reported serial numbers (124, 234, 274, 298, 344, 397). Amazing to think that for many years this model was only known from one advert drawing, and some collectors believed it never existed as such, and the illustration was just artistic licence.
However, I must correct some of the assertions made in the linked article about Frank Clarke. Perhaps this article was written before 2008? If so then it needs some serious updating.
The article makes such statements as "Unfortunately, concrete biographical information about Frank Clarke is sparse" "It is believed that Clarke operated in Birmingham" , "The precise timeframe of his activity is unclear, though estimates suggest it falls between the 1916 and 1940s". "Despite the obscurity surrounding Frank Clarke himself".
In reality more is known about Frank Clarke's early life, his products, his changes of premises etc. than any other individual airgun producer.
John Atkins' many early articles on Frank Clarke, The Encyclopedia of Spring air Pistols , 1st and 2nd editions, provide abundant data about Clarke (who incidentally lived from 1876 to 1937, and started his own gun making business in 1900.
One other point of error is the suggestion that Clarke's pop-out Briton was a potential precursor to the Mark 1 Titan. The Briton was made from 1925 onwards (not 1916 as suggested by the author) so could not have had any influence on the Titan, which we know for sure first appeared in 1916.