Here we go
The authorities have made a pigs arse of every numbering change they've implemented, and Ofcom in its brief existence has shown an above average lack of talent in their attempts to make premium rate, free etc etc make any sense. All any of these clever schemes have done is muddy the water - while I know pretty much which number ranges are likely to be expensive, the variations within a range can be massive.
There are only two things Ofcom consider any good; market forces and making people pay for things. Apparently this magical thinking is all it takes, only it doesnt work, which is why some companies are hording vast swathes of spectrum.
Applying the same to numbering will guarantee two things; consumers will pay more for phones, and companies will force phone number changes on users to add miniscule amounts to their bottom lines. As ever the unintended consequences of Ofcoms primary school intellect will fall directly in our lap, and the fix is sure to take a lot longer than the original fuck up.
They'd probably have more luck getting it right by soliciting suggestions from a primary school class and choosing one at random.