Bhamver Fateh Singh has provided an example of the oppression that Chamar and other low caste people experienced and I agree with what he/she is saying. In this day and age it is not as extreame because of laws and change in social status as people are becoming educated and richer. I also live in Birmingham and i grew up in Lozells, I go to Guru Ravidass Gudwara on union row. When somebody asks me what religion I am I say Ravidassia and I explain what this means. This my identity and we need to create an awareness.
The impression I get from sikhs (friends, colleagues) who do not know much about it is that it is some what distant to sikhi. We believe in the Granth Sahib, the teachings of the 11 Guru's aswell BUT we also believe in the teachings of our Guru Ravidass especially around EQUALITY. Guru Ravidass was not Hindu and like Guru Nanak he did not have any religion but GOD.
The reality is that people like power and if they can exercise this on others who are weaker (economically, socially) they would to make them selves fell superior.