But the findagrave page shows George Renwick as the father of a male (irrelevant here) and of a female whose maiden name was Gloria Joy Renwick and whose married name was Minshull. Can Gloria JoyMinshul, nee Renwick be the mother of Karla when Karla's parents were William John Middlebrook and Julie Renwick, whose married name was Middlebrook (not Minshull) and who had a sister Florence (whereas George Renwick is shown as having had one daughter, Gloria Joy, not two)?
ETA: In conclusion, ladies and gentlemen of the jury, I do not think that the George Renwick on the findagrave page and his spouse Eleanor Renwick, nee Marco can have been Karla's maternal grandparents - nor, to bow in shame at my own too-hasty thought, do I think they can have been her paternal grandparents either.