Maybe the descendants of one of my grandfather's siblings knows more.
Heres the marriage of one of your grandfathers siblings (via GRONI).
Marjorie Melville to Ernest Ard 24th September 1923 Belfast
Belfast Telegraph - Friday 17 April 1953
Death Notice
MELVILLE April 16, 1953, Eleanor Melville, 15 Comber Road, Dundonald, widow of William B. Melville. Funeral from her son-in-laws residence, 2 Ardgreenan Crescent, to-morrow (Saturday), at 10 a.m. to Holywood Cemetery. Deeply regretted by the Family Circle.
1951 Belfast Street Directory
Ardgreenan Crescent (at 3 Campbell Park Avenue)
2. Ard, E. J., sheet metal worker
https://www.lennonwylie.co.uk/acomplete1951_2.htm1911 census.......Ard
Residents of a house 35 in Ravenhill Avenue (Ormeau, Down).
http://www.census.nationalarchives.ie/pages/1911/Down/Ormeau/Ravenhill_Avenue/216528/KG