Hi Alexj
Welcome to rootschat

There are marriages for George D and William H on lancashireOPC so they can't be the same person
http://www.lan-opc.org.uk/Search/tocs.htmlMarriage 28th March 1880 St Michael in the Hamlet, Aigburth, Lancashire
George Denwick Sandman age 22 Sugar Refiner Bachelor of Beaufort St
Louisa Dickson age 18 Spinster of Mann St
Groom's Father George Sandman, Sugar Refiner
Bride's Father Robert Dickson, Ship Joiner
Witnesses Robert Dickson and Mary Ann Sandman
Marriage 25th December 1883 St Thomas, Liverpool, Lancashire
William Henry Sandmann age 21 Brassfinisher Bachelor of 7 Kent Square
Agnes Hamilton Carter age 21 Spinster of 4 Egerton Street
Groom's Father George Denrick Sandmann, Sugar Boiler
Bride's Father John Carter, Hair dresser
Witnesses Robert Greenhill and Mary Jane Christie
Rosie