I sympathise with the father but 'm a bit uneasy with this for several reasons:
a) Surely the failure in this case was the police not acting on the woman's complaints of harrassment/violence etc.? The problem doesn't seem to be an absence of a new law that allows people to find out information they don't have but a failure for police/authorities to act on the concerns people know about?
b) How exactly do you establish someone is genuinely a partner/prospective partner? Doesn't this basically allow anyone to phone up the police and ask for anyone's history of violent convictions?
c) Surely the point where you have to check with the police whether your boyfriend's likely to murder you is the point where the lack of trust/security you feel around your boyfriend means the relationship's pretty much fucked anyway?
Anyway, discuss. If you like.