There used to be a Harry Ramsden's down at Newhaven harbour near Edinburgh: had a sit-in restaurant and a take-away (aka cairry-oot!). My husband managed to persuade the take-away to do us lovely portions of halibut, less than half the price in the restaurant. Next time, the guy at the counter says, " We don't do halibut to take away", to which hubby says "You did last week": that strategy worked for a while.
Otherwise, fish and chips in Scotland generally means haddock rather than cod, and regional variants on what you have with it. In Edinburgh the default is "salt 'n' sauce", the sauce being like a rather runny HP.