There are a few issues here which need teasing out.
The first is the knee-jerk reaction along the lines of "Bearded baddies want to chop off your hands" stylee, which doesn't help anyone.
The second is the issue of individuals voluntarily going to someone/somewhere to arbitrate over a dispute.
The third is the "fairness" issue of the arbitration process and whether it is compatible with English law.
The fourth is the issue of intimidation. i.e. people being forced to go to, and accept the rulings of such panels under threat of violence.
Fifth - Has criminal law been broken? If so, the only competent body to deal with that is the state.
Sixth - Transparency of the arbitration process - I never have been a fan of communities isolating themselves from everyone else on grounds of things like religion or ethnicity. This makes it harder to hold those "at the top" to account.