Yes , George married twice.
Elizabeth died between 1839-1843 ?, Mary Brown was his neighbour.
I have nearly all the D & M certificates & a front page of a family bible register that lists - George Muir , Elizabeth Robb, Mary Brown.
It also has the 8 children's birth dates from 1830 -1852, but i could only find the births for Andrew & Margaret registered at Wishaw. No reg birth records for any other children.
MUIR
ANDREW
GEORGE MUIR/MARY BROWN
Birth 17 AUGUST 1846
Bap 6 SEPTEMBER 1846
WISHAW RELIEF
LANARK
MUIR
MARGARET
GEORGE MUIR/MARY BROWN
Birth 17 APRIL 1852
Bap 25 APRIL 1852
WISHAW RELIEF
LANARK
George was born at Biggar abt 1800's & between 1844-1846 moved to Overton, Cambusnethan.
George's son George ( b1837) a photo of his home shows "Nemphlar" Lanark, &
Thomas (1844) newspapers shows his birth as Stonebyres , Fall of Clyde & sometimes Biggar.