The Huguenot Ancestry of the Mallalieus of Saddleworth was written by D.F.E. Sykes (1856-1920) and first published in 1920.
Under the current terms of the Copyright, Designs and Patents Act 1988, the copyright of literary, dramatic, musical or artistic works in the United Kingdom expires at the end of the period of 70 years from the end of the calendar year in which the author dies. Authors who died prior to 1925 were not eligible to have copyright on their works extended under the Duration of Copyright and Rights in Performances Regulations 1995, and their works were protected for a period of 50 years.
As Daniel Frederick Edward Sykes died in 1920, copyright on his works expired at the end of 1970 and was not restored by the 1995 amendment.
Courtesy of the Internet Archive.
The PDF version of the book can be downloaded here.