aghadowey,
Many many thanks for your response which has added another couple of pieces to the puzzle.
kingskerswell,
Thank you also for your interest. You raise a valid point which I can't really answer in respect of Samuel and Jane. As I understand it, Samuel bequeathed his farm to his oldest son, John, who then ceded the rights to it to his brother Andrew, (who subsequently sold it to the railways), so he could enter business in Limavady.
From what remains of the family memory, it appears that John moved initially into Catherine Street, and then to a property in Main Street (No 5?), which was then compulsorily acquired possibly due to historic significance. He then purchased both 6 and 8 Main Street together. He and his family lived in one, while the other was established as a school which was run by his elder daughter, Ada Cunningham, my Grandmother, until she married in 1913 and left Ireland to travel the world with her husband before settling in Australia in 1919.
My auntie met the son of the subsequent owner of the Main Street house here in Canberra where he had also settled some 20 or 30 years ago. Small world!
Thank you again for your interest and assistance. I am still very interested in more details of the Cunninghams and Fergusons if anyone has any information to offer.