If you're looking for Margaret and Robert John Clague sister and brother, I can't help you although in 1891 they would have been 27 and 24 respectively. If you're looking for Robert John Clague who's wife was Eleanor Lizzie Kaighin, I think Brian Lawson's listing on Athol is your man. They had a child, Robet Kaighin Clague Baptism January 22, 1893, Onchan, IOM but resided 66 Athol St. Douglas. LDS Film number 454980.

Robert John Clegg married
Marriage record Onchan Village, IOM LDS film # 454980 Marriages 1884-1891 Film also contains baptisms and burials.
#265 May 20, 1890 Robert John CLAGUE Full age Grocer resident of Douglas. Father's name Robert CLAGUE -cooper married Eleanor Lizzie Kaighin full age of Onchan Village whose father was John KAIGHIN -a farmer.
John Edwin Killip, Annie Semiah Kaighin, and Robert Skillicorn c.p. witnessed the marriage. Both signed.

I don't know whatever became of sister Margaret Clague.