Dementors in the Privet neighborhood

[Kemper]

No: HPFGUIDX 150241

Amiable Dorsai posed:
Why could the Dementors attack him?  They weren't sent by Voldemort.

Kemper now:
Much like House Elves and Phoenixes are able to Dis/Apparate in
Hogwarts, perhaps something similar can be said about Dementors being
able to attack Harry within his home (here meant not only #4 but the
neighborhood of #4, as home may mean more than just a house.)

So whatever ward/shield charm protects Harry's Home, it doesn't seem
as though that charm includes any Patronus derivatives, nor a
derivative of whatever Snape endorses to deal with Dementors.

-Kemper