AsCarol says, there is no evidence of domestic violence being greater among certain ethnic groups (even westerners Lox).
Re honour killings, 12 may be the tip of an iceberg.
Police estimate at least 12 are dying each year in the UK but others will be hidden – forced suicides and murders made to look like suicide are widely believed to take place undetected. Women aged 16-24 from Pakistani, Indian and Bangladeshi backgrounds are three times more likely to kill themselves than the national average for that age and it is impossible to tell what pressures some must have been under. And for every woman who dies, it seems certain that there are many, many more living with honour-based abuse and hidden away in shuttered communities.
The full Guardian article is here.http://www.guardian.co.uk/society/2009/oct/25/honour-killings-victims-domestic-violence
It makes clear that it is not just a Muslim problem, but all the examples given are.