Small Holes in the Load Bay of Defender 110 Double-Cab

Been trying to fix as few things on my Defender 110 Double Cab.
After cleaning out the rear pick up/load space (1st time in a few years!), I've noticed four small holes in the floor. Some of these have the white powdery corrosion surrounding the.
Wondering about the best approach to fixing these?
Should I treat the corrosion and cover the entire floor area with a sheet of checker plate?
Maybe drill the holes to a round shape and insert rubber gromets?
Any thoughts, suggestions would be gratefully received.

You could drill them out, paint and put a grommet in the hole, pointless just covering it up.

Welcome to LZ.

Google crossmember/floor supports corrosion.

It's coming (up) from underneath the floor ...

Do not cover over with checker plate. Treat the problem.

You can get proper replacement panels rather than using chequer plate. And if you want to ignore the problem a sheet of stable matting over the top will be just as goo das anything else and then also acts to protect the floor from anything you load in the back and acts as a sound deadening. Mine is still awaiting being done but I am swapping out the hardtop tub so am not bothering to do the work at the moment.