Hi,
You're welcome!
Also I forgot to add that if Mark was alive in 1871 (census, living Blasterfield Crosby Ravensworth with his brother John), he couldn't have died in 1868!
Going back to your original question, in order to get your Robert's father, it would be helpful to order his marriage cert. That way, you wouldn't go off on any wild goose chases!
I may have Robert in 1861:
Robert Elwood age: 25 b1836, Boarder, born: Cumberland, England
Civil parish: Toxteth Park
Ecclesiastical parish: St James
County/Island: Lancashire
Registration district: West Derby
Sub-registration district: Toxteth Park
ED, institution, or vessel: 1a
Household schedule number: 83
Piece: 2697
Folio: 6
Page Number: 14
Household Members: Name Age
Margaret Elwood single 39
Jane Elwood 42 Sister in law (to Head)
Robert Elwood 25 Boarder, Baker
All born Cumberland
Do you have him in earlier census?
Regards,
Gillian