The UK DNA database - obfuscation and utility

Here's a report criticising recent Government pronouncements on DNA data retention (one of many to surface on the internet today) Public being misled over DNA benefits - Public Service.  In the runup to the UK elections, the main political parties are jostling for the right message - in this case, to be seen to be "tough on crime". Having been smacked down by our European protectors (at least where human rights and privacy are concerned), the Government still plan to keep DNA fingerprint data on unconvicted individuals for a considerable period.  Everyone collared for an offence has there DNA sampled and fingerprinted.  It's what happens to those data if said individual is not charged, or is found not guilty of the offence that's the issue here.  In Scotland, this is limited to 3 years.  In England, the Government proposes to hang on to these data for 12 years in cases where the individual was charged with a serious offence, or 6 years where the charge was of a less serious offence. Pause to think.  In both situations, the individual will have been found not guilty.  So the Government is effectively suggesting there are two degrees of innocence!  Someone found not guilty of rape is somehow less innocent that someone found not guilty of car theft. A further point is that the case being used to argue for long term DNA data retention does not in point of fact support the retention of DNA data from unconvicted individuals.  As the article points out:
Because Bowman's killer was arrested after a pub brawl, Labour has claimed he would have been much tougher to find under Tory proposals as his profile would have been deleted. But GeneWatch said the killer, Mark Dixie, was arrested after the murder. This means his DNA did not need to be retained for an indefinite period as it would have been checked against the database at the time of the arrest. It said there are "numerous other high profile cases cited by ministers" that also did not require the retention of innocents' DNA. "Murders solved by keeping innocent people's DNA records are as elusive as the weapons of mass destruction in Iraq," said Dr Helen Wallace, GeneWatch's executive director. "If the government has a case to make why can't it produce the evidence?"
Genewatch also claim that "crimes brought to court following DNA detections have not increased since 2002/03, despite the DNA database more than doubling in size."  How much truth will be sacrificed in the pre-election posturing?