I'm tempted to connect the Robert married to Agnes MURRAY as being one and the same as the Robert bap. 1740 to William RICHARDSON and Janet DOUGLAS.
BUT naming pattern of Robert and Agnes' children indicates that although Janet is obviously an important name for the family, she looks to be the eldest daughter, indicating Agnes MURRAY's mother, rather than Robert's, and the first known (to me) son was a Robert. Her parents may then be John and Janet MURRAY and his Robert and Agnes.
All of which is assuming that the naming pattern was important to them, and we have the first four children identified.
The other niggle is that although Robert was indeed baptized in Kelso, two years later the family were in Linton and 6 years later, Crailing. Did they return to Kelso?
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