Hotpoint FF40X Fridge Freezer?

I have a steady stream of water dripping down from the right hand side of the vent behind the top freezer drawer which is then freezing in the middle drawer and botton of the freezer daily. (looks as though it may be defrosting itself and then refreezing.)
I have tried various temperatures, but it makes no difference

I have tried defrosting the freezer but it is still happening, can anyone give any advice please?