By ordering any of the other certificates that will prove who their parents are and not George Alexander Sayles parents. That information on the other Sayle childrens certificates should tie in with what is on IGI and Brian Lawsons site ie James and Harriet as parents but doesnt prove they are Georges parents.
George went to Canada in 1885 so should be on 1881 Census. The only George A Sayle on 1881 Census is the son of a Thomas and Mary. Had George written down his parents names or had this information come from the Quarriers aftercare service - could they have got it wrong? Had George written down his siblings names or was this from Quarriers also? With so many children of same surname just wonder.....
As registration of births not compulsory until 1878 a search of baptism records 1871/1872 for any George Alexander Sayle/MacDonald may show something? Not sure if the birth date was recorded on the baptism register if anyone willing to do a look up for Cory? Just a though but a real mystery!!
ps Looks like the children Harriet and Annie are one and the same. In 1891 Census Harriet snr is recorded as Annie.
Also, couldnt find any Charlotte or Laura.