I've just been reading through and absorbing all this, and maybe a little summary would help some of you folks.
These records have been posted in the thread, from FreeBMD:
http://freebmd.rootsweb.com/cgi/search.plLouisa was actually born:
FREDRICK Louisa March 1854 Plymouth 5b 265
Her mother didn't marry Peter SANTILLO until 1857:
Frederick Eliza Plymouth 5b 400
Santillo Peter Plymouth 5b 400
But Louisa was obviously reared as a Santillo (even if Mr Santillo was not her father) and married as Santillo in 1873:
ROWE William Henry Stoke D. 5b 637
SANTILLO Louisa Stoke D. 5b 637
However, she was estranged from Mr. Rowe and partnered with (and had children with) Mr. Lishmund before marrying him in 1885 (after Mr. Rowe died):
LISHMUND Charles Stoke D. 5b 602
Rowe Louisa Stoke D. 5b 602
I hope that helps anybody new coming along who hasn't managed to follow the twisty trail.

(The 1891 census was posted already in 2010 -- best to read the thread before starting to duplicate what has already been done. The easy way to read the entire thread at once, in start-to-finish order, is to click on the PRINT link in the upper right, and that will show the whole thing.)