What's the point of Clare's Law? Watch
Apart from the apparent mismatch of the law and Wood's death - presumably she'd have dumped him sooner and then he'd have killed her sooner because the Law says nothing about the cops protecting potential victims - how does it actually help anything? I think it highlights two flaws if it is used, one with the legal system and the other with the relationship in question.
Firstly, if you have reason to suspect your partner is abusive, you already need to get out. You don't wait around for the police to tell you s/he (yes, despite the misleading name, it's available to men to ask about their partners' histories too) has a history of beating up their partners. You even don't need to wait around to be told they haven't attacked anyone yet, if you have reason to believe they are abusive. What you really need is protection if they go nuts when you dump them, though really you'd need protection until they found another potential victim, and the cops would then tell them to dump the criminal and so on and so on.
Secondly, the fact that the law acknowledges past crimes are still relevant to the extent that people's lives depend on it is an admission the prison sentence/rehab/whatever is grossly insufficient. The point of Clare's law is to try and save people's lives - this means the police have identified potential murderers, who already have violent histories that have not been resolved. The fact that Clare's Law exists is proof the legal system is not fit for purpose because we certainly should not be releasing criminals confident that they'll kill someone else. It's effectively saying "Yeah, we know this guy brutalises people and will do so in future, we haven't really bothered rehabilitating his character so we'll just point him out to you as someone to stay away from when we release him" - madness. And again, there's no provision for properly protecting the dumper from the dumpee.
I think there is scope for the friends and relatives to use it to convince someone so smitten by love they can't see someone's true character. But the rest of it seems pretty useless to me, even if very well intentioned.
All the police records do is (I've had similar discussions over CRB / DSB checks) show what they've been convicted of. I'm sure there are many people out there who are abusive who haven't been caught yet.