The statute essentially set up the position of the Director of Public Prosecutions in order to make clear the independence of the function. Arguably, for those of us who remember when the prosecution service was part of Justice, there was functional independence being exercised, but it wasn't as apparent, perhaps, to the public.
In terms of independence, the statute has really set out the scheme by which the Attorney General is kept informed of issues of general interest, but unless she chooses to intervene, the final decisions on how to bring matters forward and the guidance to give prosecutors are mine. In terms of assuring the independence, I think the statute has set that up quite nicely, and in practice it's not an issue that arises very often.