The Drouin Collection at ancestry.ca has a baptismal record for Louisa Ann Greggs, d/o William greggs, Corporal in the Grenadier guards and Mary, his wife (no maiden name given). Louisa b. 17 June 1842 and baptized 23 Oct 1842 at Anglican Garrison, Quebec.
An online family at ancestry shows a marriage for Louisa to William Morse 23 Apr 1863 Middlesex, Engl and death 03 Jun 1943 Queensland, Australia. The same tree shows a sister, Mary Adeline, born 2 Oct 1844 Chelsea and death Jul 1849, brother William Henry 1848-1915 and another sister, Emily b. 1851. This tree shows William Henry Griggs b. 1810 and d. 1849.
Their tree shows Griggs with Greggs in brackets for the surname spelling.