Peter, that IGI entry is a LDS Church member's one, and looks as though the "Birth: About 1852" has been guessed from the death date given of Dec. 1940. If they had said where that death was recorded so that you could check it, it might have been some use to you!

All I can tell you for sure is that there is no sign of a Malvina or Christina Quirk or Robertson in Maughold bapts.

Have you checked the English GRO birth indexes quarter by quarter over several years for both surnames?

Sue