So I syphoned around 6 litres of water from the floor pan today - didn't have time to remove the seats and pull the carpets back!

Had a look in the plenum chamber - think I've found the O/S drain, about 25mm in diameter - its under the brake fluid container? - it looks in bad shape, very cracked. Couldn't see another one like it - I'm just presuming there is one on each side?
However, just to the right of this drain is a hole around 40mm in diameter - looks like it should have some form of grommet in it, but it hasn't - should it have something in it??

I take it the drains are replaceable??