That would be a matter of policy by the Chief Constable of the force area, hence me using the term "policies and opinions".
For a matter like this, it is likely that ACPO(S) would have discussed policy and agreed what line to take. It is likely that they were simply making the point that the re-classification from B to C did not alter the fact that the offences themselves were extant. They were also making the point that to flaunt (or inded flout) the law is such a flagrant manner was stupid.
I fully expect them to take the position that user quantities will not be treated in a criminal manner. Customs have been doing this for many years, for first offences. User quantity of dope = fine. Do it again and there will be more severe penalties.