Thanks for the info ,the 1841 census is for "linnhead" Nemphlar, the 1851 census shows Andrew 4 born Cambusnethan,the 1861(taken in Cambusnethan) shows Andrew & Margaret born in Overton.
The person researching Nemphlar ( i have a family photo of the house with a relative writing 'the house where i was born George J Muir') sent me the 1841 details & says the cottage became unoccupied between 1861-1871.
I believe its all connected somehow but I can't find anywhere to say all these children are his siblings as I can't find their birth details to say all their parents were George & mary Muir.(& can't find any marriage except 1843).
1841 census shows wife away that day. Has she died after Peter's birth 1839 & George remarried?

Being an Aussie I have checked resources on the net = Familysearch, also spent a 'small 'fortune on Scotslandpeople.
Now that I have totally confused all of us I'll end now & I am so pleased I don't get charged for each word I write.
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