Just a bit of newspaper trivia in case the street names help:
Exeter Flying Post 06 August 1892
MARDON - DART- Aug 1, at St Paul's Church, Exeter.
Henry James Mardon to Edith Emma Dart, both of Paul-street, Exeter
Western Times 20 January 1899
Deaths
MARDON - Jan 14, at 34, Rosebery Road, Exeter, Henry James Mardon, age 32.
Exeter and Plymouth Gazette 13 January 1900
In Memoriam
MARDON. In loving memory of Henry James Mardon, who fell asleep January 14th, 1899
"A light is from our household gone,
A voice we loved is stilled
A place is vacant in our home
Which never can be filled."