I’ve not had this before with previous Land Rovers I’ve owned, the floor panels are quite badly corroded. At the moment I have to watch my budget. New panels are very cheap but the expenditure has been higher already than I anticipated so I have fixed them up as best I can for now, they are easy enough to replace later on.
I snipped out a good strip from the discarded side panels and pop riveted and glued them to the leading edges of the floor panels. (The holes were bigger than large penny washers). I then flattened the pop rivets and used body filler and many layers of old paint to seal any remaining voids Seems pretty sturdy now.