We are all most definitely here Nesta.

Maybe Nat doesn't approve of Guy Fawkes celebrations - he's a fairly conservative lad and make not like the festivities.
And yes Daisy, Nat has referred to Granny Shepard as "Dame" before.

I think it's his little joke. I get the feeling she is the matriarch of the family - probably does all the cooking and cleaning for all the families "rooms".
Nat hasn't written about the family for a while except that brief mention of his mother's illness. No random stranger has had a birthday for a while either.