To be fair, most of the immigration to the UK has been fine. The Sikhs and Hindus have been great. Muslims were fine until the late 80s. There were racial issues and tensions with the black Caribbean community for years, but that settled down years ago. And of course you have Chinese/Asian immigration, who have been terrific.
I am no hippy trippy PC person, but overall, despite some issues and problems, the ethnic immigration to the UK has been positive. At least from the 1940s until recent times.
It seems some are less happy and more concerned than you.
Of course, most reports concentrate on the downsides and not any positive aspects, as there may be.