Is there a flaw related to the Berne Convention?
The Berne Convention states very clearly that you cannot allow copyright works to be used in a way which detracts from the copyright owner's ability to earn a living; as a signatory to Berne, the United Kingdom would be in breach of the convention if they enact domestic legislation which limits the rights of copyright owners to profit from the work that they create.
Article 5 of the Berne convention states that authors receive copyright protection without the requirement of any formality, such as having to register their work with an agency or collective society; Article 9 of Berne grants authors the exclusive right to authorise the copying of their work.
There can be no clearer example of limiting the rights of copyright holders to profit from the work that they create than legislation which permits the
commercial use of orphan works, especially if you are required - even on a "voluntary" basis - to register with a UK based agency as part a mechanism to minimise or prevent such exploitation.
It seems to me the balance will vanish once the registration mechanism is set up. That shouldn't take very long.
I'm in favour of a UK or EU registrations body (especially if it broadly mirrors the US system) but not if registration is
required or preferred to protect ones works against the potential of being exploited as "orphans" by less than scrupulous entities.
My rationale isn't based on my own business, but on the millions of people whom upload their own images to sites such as flickr, Instagram, Pinterest, Facebook etc. - casual users of image sharing sites whom probably have no idea about copyrights. Remember, the language of the ERRB applies to all works, not just those created in the UK.
Creative professionals might know to register their works to protect them, and will have to suck up the time/expense of doing so as a cost of doing business. Joe Average might not be cognizant of how his pictures, designs or so on could wind up being appropriated - and there's a good chance he won't be able to afford to register his work (factoring for the current economic climate)
The US recognizes copyright exists from the moment created, but also requires registration for the purpose of assessing statutory damages and penalties.
A registration is technically required only before you can file suit in federal court; the registration needs to be timely (within three months of publication of the work) to permit a claimant to pursue statutory damages of up to $30,000 per work infringed - or $150,000 in the case of wilful infringements... otherwise the claim can only be for actual damages (usually the "lost" license fee) and/or DMCA violations.