Haven't got mine .. mustn't exist.
Moan, moan, moan .. just fill it in ... helps the Government to deal with housing, jobs, health, etc., where money is needed most ... ancestry is just a bonus.
Fill it in very clearly. Years past, lots of the enumerators spelling of some the names was lost in the translation of their fancy writing.
Think will be very difficult for our off springs to find out their true past, what with no marriages, multiple marriages, children with lots of varying fathers, step-children, single mothers, etc. So, if you get a minute, write it all down now for them. They will thank you posthumously.