if you were assaulted by police on April1st - why not report it as a hate crime?
" I was verbally abused and physically attacked by members of a large, angry group of armed, masked (mostly) men simply because I was part of a different group. "
http://www.met.police.uk/communities_together/docs/reporting_crime.pdf
report it online here
http://www.met.police.uk/reporting_crime/index.htm