JoanK - you are so right (just typed "tight" which has quite another meaning here...). As I have probably already said (apologies) there is a huge amount of anti-English prejudice in Aberdeen, and my son was the butt of it for years at the local school. He is quite sensitive and used to get so upset, especially as whenever racial prejudice was discussed in social education lessons, all the children would insist they were not racist - they were never horrible to the one Muslim boy in the class, probably because he was perceived as "cool", but my son was not cool and as a result was verbally tortured for years - it only really stopped in 5th and 6th year, when some of the worst offenders had left school, and the others had at last grown up a bit. The families of these boys were perfectly respectable - the school was in an affluent area - and I can only assume that the parents had similar attitudes. They simply did not see what they were doing as prejudice.
My elder daughter also suffered a bit at her school in Aberdeen, but she is the master of the put down and it soon stopped.
Fortunately my daughters have not encountered anything like this in Edinburgh, which has a much more cosmopolitan population. And so far everyone in the village that we have just moved to has been really friendly, many people have come round to say hello, we have been invited to the village barbecue later this month, the girls have been asked out to play in the street with the other children - when we first moved to Aberdeen nobody spoke to us for weeks!
My mother's late sister lived in South Africa for the whole of her married life. Both she and everyone I ever met through her always said that they were "not racist" and that apartheid was "necessary" because the black people were somehow inferior. I was always amazed that these otherwise pleasant and well-educated people could spout these views; as you say, their prejudice was invisible to them.
Rosemary