Nissan Micra (52 or 53) - Cant unlock Nissan Micra either Remotely or Manual - KLJ

Hi - I can't unlock a Nissan Micra that has been standing for about a year. Neither of the keys will unlock the car remotely or manually (via passenger side door). Do the batteries in the keys need to be 100% to unlock the car manually ?? - I am pretty sure that the car battery will of course be flat but I would have thought that would not have affected opening the car manually ?

Any thoughts or suggestions would be gratefully received!

Many thanks