it looks like I was wrong, Kathyan's given you the answer. In that case you will either have to tell your partner or make sure he never sees the marriage certificate.
I would contact the Registrar ( well it will be a clerk ) and discuss
we both in the same room got the third degree over our parents and their occupations....I concluded that it wasnt by chance but to hinder impersonation ....
As PP and others have said, you will be quizzed about each other before permission to marry will be granted, so you'll have to tell him about your name change.
You will both be signing the marriage certificate at the same time. It used to be just fathers names and occupations that had to be put on it. However from 2018 I think that both parents names would possibly be included and if so he's bound to ask why your name is different. I would definitely tell him before not after.