Cultural clues to locations/origins

[Amy Z]

No: HPFGUIDX 22696

Susan Hall just sent me an offlist post that gave me all sorts of 
illumination about Neville's possible home that only a British 
citizen could give.  So I am wondering:  are there other such 
assumptions that you Brits carry about the characters that you might 
not even think to mention because to you they're obvious, if you 
follow me?

I don't know how to ask the question more specifically because these 
cultural clues are invisible to my American eyes.  But it comes up 
now and then--e.g. someone recently said Ottery St. Catchpole sounded 
like it was in the West Country.  Are you all carrying around secret 
information about where Little Hangleton and Cokeworth are and where 
Dean and Lee and Madam Pomfrey hail from?  Say more, please!  

Amy Z
ignorant Yank eager to learn