i see the media were most reluctant to report the racial element of this
Really ? All the coverage I saw/read mentioned it , often in the headline or first paragraph , must be some strange media you are viewing .

the gangs were asian and black and were fighting each other
And also asian against asian and black against black , look at news from the past 5 years from Lozells and surrounding areas (or even further bach if you wish). Gang warfare where what road/estate you live on is just as "important" as your ethnicty , where you drink , where you eat or what clubs you go to .