How does DD know what Petunia/Vernon said?

[justcarol67]

No: HPFGUIDX 156751

Rebecca wrote: 
> Perhaps a hidden wizard painting that can hear what's going on in
> the house????

Carol responds:
That's a really good suggestion, which would explain how DD knew that
Vernon was threatening to throw Harry out and Petunia was in danger of
capitulating, though the wizard would have had to be a quick talker. 

It might also explain how "the sender of the letter" in SS/PS
(McGonagall?) knew that Harry had been moved from the cupboard under
the stairs to the smallest bedroom, though it wouldn't explain how the
sender also knew that the family had moved to "the Hut on the Rock,
the Sea." (Maybe the letter magically "knew" the address, just as owls
seem to know how to find the recipient of a letter, even without an
address?)

Still, I like the possibility of a hidden wizard painting better than
chocolate frog cards, which Petunia certainly wouldn't have in her
house. Not that she'd want a hidden wizard painting, either, but maybe
it was part of her bargain with Dumbledore. Woe to Petunia if Vernon
ever finds it!

Carol, who thinks that the instruments on DD's desk are another way
that DD could watch Harry more closely than he knows and hopes they'll
be explained in Book 7 despite DD not being there to do it himself