My 2014 Defender 90 has wet carpet passenger side - not sure if the AC drain is blocked but can’t find it. Also could it be the bottom door seal ??
Move to defender section. Since they are similar to the disco. At the front of the drivers or passenger door, slide under the vehicle and look at the transmission tunnel and look for the black hose on each side of the transmission. They will have a rubber nipple at the bottom. If clogged they will leaks some nasty water and such out when you clean the tip.