From Vintage Patterns wiki:
Blackmore Patterns were published by The Blackmore Fashion Co., Ltd., Town Hall Buildings, Bletchley, Bucks. It was an English Paper Pattern Company working from 1845 until the 1940s. (Source)
Patterns have various names: Blackmore; Blackmore Fashions; Blackmore Pattern; Blackmore Patterns; Blackmore So-Easy; and Pattern by Blackmore.