I'm in a position to judge from my personal experiences and I think that's all you can go by. Imagining how someone else feels is neither here nor there and lends no ascription to the discussion.
When I was a kid growing up in Shepherds Bush I went to Christopher Wren which was very multi-national and in a working class area. ( White City estate doesn't come any more working class than that. ) I don't recall one incident which can be attributed to race colour or creed. There were fights and scuffles of course, but they can be attributed to the most ridiculous of petty reasons, football teams, practical jokes etc. I do recall one afternoon during play time that someone mentioned that 'NF were outside the school handing out leaflets' and the kids black and white alike went out there en masse to see them off.
As for now, why do you assume that the people I know from other countries are middle class? The four blokes who come and clean my windows are from Hungary and have built up a successful business and have started families here and are very happy. My neighbour opposite is German, she's very happy and has an active role in local community issues on the residents association. The Polish fellow around the corner can never fit me in to do any work as he's too busy. His wife works in our local coffee shop and are looking to start a family here. Our local convenience store is staffed among others by French, Romanian, Venezuelan, Indian and a Spanish woman. They all appear to be fine, I talk to them fairly frequently and their main concerns seem to be getting their work and family life balance in kilter.
The local BUPA home where my sister is being looked after is staffed almost completely by foreign nationals. While they feed my sister I get to speak to many of them. They may have concerns but they tend to be more about everyday matters, lack of money, travel and so forth. None of them are complaining about this country or the way they've been treated. It's very much to the contrary.