Here is some information about Choppington from an archiac tome of mine published in 1825. It says of Choppington,
"Choppington, or CHABYNTON, lies at a short distance west from Cambois, and four miles east by south from Morpeth. It is a small village, and gives name to a township. The first proprietor of Choppington was Hugo de Hexham, of Newcastle upon Tyne, who held the manor of the lord bishop in capite, by fealty and six marks rent. The family of Wilkinson, of Wystoe, also held lands at Choppington and Cambois. South and North Choppington now belong to Mr. Cook and Mr. Clarke. There is a colliery winning here. The Guide Post is a small hamlet, consisting of six houses, including a public house."
Sadly no mention is made of Scotland Gate at the time of publishing in 1825, which fits in with it's apparent non-existence and Michael's comments re the maps of the era.
I wonder what might have been said about it in the huge 10 volume work about the History of Northumberland published in 1909. I shall go and find out and report back.
Philip