Nothing can be done about shitty people who dump inconvenient animals - well they can be prosecuted of course, but it's not the highest priority crime to investigate and I mean it more about their character, those who are cruel to animals are shits.
The puppies will probably need to be put down (or even if these are just in time, the next abandoned litter won't be)
When the amendments to the law come in, there will be payments to support the euthanising of newly banned dogs. Breeders have already been advised a few weeks ago, to desist from further matings - canine gestation is 9 weeks which now extends beyond the enforcement date.
There was a possibility that the last legal generation would command premium prices. If dumpings have started then it looks as though the bottom has fallen out of the market instead.
At least dumped puppies are unlikely to pose a risk to the public. If the now valueless adult breeding stock dogs are abandoned there may well be a different risk profile