Brian Gaff wrote:

ERm are these for the square spindle things with the tapped holes in them,
if so its the square bit that needs to be newish. Mine are imperial here.

I changed the door handles here, that required changing the square bar
from imperial to metric, the new handles expected to be able to have
bolts running through the door where the metal body of the latch was in
the way, so I had to refit the latches and then the strike plates ...