But in my experience british people are just not very big on birthdays.
They never invite the family over for a meal. They do send a card and they do get the children a present, but it is not something they (my husband's family) consider an event worth celebrating, unless of course they turn 50, 60 or the like.
In my country, we sing for the birthday boy/girl/man/woman to wake them up, presents in bed, nursery/school friends are invited over, then the family in the evening, with singing, presents, flags and cake.
I always invite the family over for both the children's, mine and my husband's birthday. Everytime it is like they don't know what to do with themselves, and it got really akward to begin with. Not once have we been invited to their birthdays(apart from when my father in law turned 60 and the entire - 80 people - family got invited). We have invited ourselves a few times.
I just think that your birthday is a huge thing. It is YOUR day, and you should be celebrated. So BIG belated HAPPY BIRTHDAY to you. Make sure that the family spoils you rotten next year. Show them how it is done.