Q's link to the Victor discography doesn't work for me, but I get the Minster Singers here:
http://victor.library.ucsb.edu/index.php/talent/detail/6859/Minster_Singers_Vocal_group, which lists them as 1905, as you have above.
However, from your earlier post I found your Google result which led to... "The Music Trade Review" of October 28, 1905 lists under "Records for November, 1903", "New Victor Records":
Old Sea Chanties
Colected by John Bradford and Arthur Fagge and sung by the Minster Singers of Londong
61145 (1) "The Capstan Bar"
61146 (2) "Blow, My Bully Boys" and (3) "Sally Brown"
61147 (4) "Whisky Johnny," and (5) "Shenandoah"
61148 (5) "Rio Grande" and (7) "Blow the Man Down"
The Music Trade Review is online at http://www.arcade-museum.com/mtr/. Viewing pages on line requires a browser plugin that didn't work for me, but you can try the page here http://www.arcade-museum.com/mtr/MTR-1905-41-17/, which also has a pdf link at the bottom.
The Music Trade Review, established 1879 (and digitized with support from namm.org), was "published every Saturday by Edward Lyman Bill at 1 Madison Ave., New York."