bosch integrated fridge freezer water build up

[kenwelld]

Hi,
Can anyone help with a small, but annoying problem with my fridge freezer. !?!
Every week I have to mop up a small amount of water that builds up at the bottom of fridge under the vegetables boxes. It doesn't seem to matter what temperature I keep it at. I've tried all different settings. The seals are fine and we have always had this problem. It appears to have two drainage channel against the back inner wall that meets in the middle where a very small hole is. There was a red plastic plug type object in this hole from new but the water doesn't seem to drain away anywhere other than collect at the bottom of the fridge. I'm not talking about bath towels needed to keep it moisture free but its starting to get annoying..!
Is the red plug type thing meant to have been left in this hole??
Is this moisture build up normal??
Where does this moisture vapour go?? Is there a reservoir at the back that I am meant to be emptying every so often?

Help would be greatly appreciated!!

 

[rocks1]

Take the red stopper out. And leave it out. The drain hole is blocked. Tip a small jug of hot water down the hole to clear it. The water will go on to the tray at the back on the compresser and evaporate.