the End of the Line by Nigel Trantor is the final historical novel in the series about the Gospatrick family. Reviews on Amazon are not especially favorable for this novel, but the preceding three novels seem to be highly regarded and the End of the Line is recommended for series collectors. Reviews on http://www.goodreads.com/book/show/423848.The_End_of_the_Line are more positive, which is why I chose this book.
I did a little research on Nigel Trantor (deceased in 2000 at 90 years of age) and discovered he was an extremely prolific Scottish author and historian whose novels, over time, became more historically based than fiction. He was a stickler for accurate historical facts.
So, if you are interested in Scottish history and enjoy learning, Nigel Trantor may be worthwhile checking out. On a final note, I was horrified to see that a new hardback copy of this novel was selling for $80 Canadian on Amazon! Kindle has it for the more reasonable price of $7.99.