Mums, Dads and Plural Surnames

Mum, Dad, Grandma and Uncle, stand on notice: You do not always get a capital letter.
Here's the drill with those relative-name-substitutions that so many people get skewed.


If the word (Mum, Dad, Uncle, Granny) stands alone as a name substitute, then it gets a capital. 
I'm going with Mum.
Dad and Grandma took me to the beach.
Hey Uncle Arthur, are you really a time-traveller?


If the word (Mum, Dad, Uncle, Granny) has a personal pronoun (my, your, their, his) in front of it, then it does not get a capital. 
I'm going with my mum.
Jane's grandpa and grandma took us to the beach.
I asked my uncle if he was really a time-traveller.


If the word has a "the" in front of it, then the word does not take a capital.
I asked the mother if she wanted to come.


Now, for plural surnames.
If your name is Jones, then you and the rest of your family are the Joneses or the Jones family.
If your name is Blake, then you and the family are the Blakes or the Blake family.
If your name is Derry, then you and the family are the Derrys or the Derry family..
If your name is Odgers, then you and the gang are the Odgerses or the Odgers family.
If you want to talk about an address, you might say, we're going to the Blakes' house or the Blakes's house. You might also say you were going to the Blake house.