It's a dump (apologies to anyone who stays there and to my 8-week-old son, who was born there ). There are bigger dumps, Greenock and Port Glasgow spring to mind , but I can see why David wanted to get out of there.
My mother was born and raised in Greenock. That part of my family can't help that that is their hometown. There are actually quite beautiful hills above the town, which held very romantic and poignant memories for my mother, of her wartime romance. It is a port town and played an active role in WWII, as did my mother's family. I visited only twice as a child, during the 1960's, and it seemed fine to me, just an average place with a lot of history, though I can't speak for what it's like now. But Greenock and Gourock are where my genes are from in the most direct way; don't like to see them knocked.
As to the original topic -- so many Scots, English, Welsh and Irish people actually have each other's blood in their veins that it's silly to think there is a "look" to any of them. There have been centuries of inter-mating -- many Scots have Irish ancestors and vice versa, and many English have Irish or Scots ancestry; we're overwhelmingly mutts, here on these British Isles. Some may not want to admit it (fiercely nationalistic Scots or Irish) but there is a lot of crossed and re-crossed bloodlines going back generations.
Living example: To the naked eyes and ear, I'm an English woman with a London accent, and I've even been on the receiving end of the cold shoulder/bad attitude for being "English", from some nitwit who evidently watched Braveheart too many times (!) -- but the fact is my parents were a Scottish woman with Scots and Irish immediate ancestors and going back for generations, and a Liverpool Irish man whose mother was English and from the Viking invader stock but whose father had an Irish father.
We are all too mixed to speak of "Scottish" or "English" looks.