Pollock is a fairly widespread name in the Glasgow area, but mainly associated with the south side parishes such as Mearns, Eaglesham, Neilston where, besides a landed family of that name (Pollock of Over Pollock near Newton Mearns), there were a number of farmers, and still are in the area. The spelling varies including Pollok, but the one you need to watch for is Pook. Some of them were sensitive about the full name in the 19th century, though why Pook was thought any better is enigmatic. Also Thomas was a frequent Pollock first name, eg the poet Thomas Pollock. The advantage perhaps is that it is an extensively researched name up to the 19th century.