I've got a Whirlpool Diplomat APM6002, which also seems to be sold as a Smeg CR325A and Bauknecht KGI2900 A.
From what I understand, this is an old-style "falling air" fridge freezer, i.e. with a thermostat and without any kind of a fan etc.
The freezer seems fine (don't know exactly how cold it is, but it is frozen). However, the fridge section is too warm and sits at about 7.5 DegC, getting warmer in hot weather.
Having read the Basic Fault Finding guide, I'm struggling to figure out what might be the problem. My first thought was that it could be the thermostat. In particular, the product manual says that a normal setting for the thermostat is "3", but adjusting the thermostat above that does not seem to cause the compressor to be turned on, and does not decrease the fridge temperature.
Any thoughts/suggestions on this would be much appreciated.
Also... if it might be a thermostat issue then I'm really struggling to access the thermostat - I can remove the thermostat knob and a retaining sliding plate, but I get stuck trying to remove the plastic housing surrounding the thermostat. Drawing of what I'm looking at is on page 3 of this PDF: http://www.bauknecht.ch/uploadsMAM/KGI%202900_A%20gb%20KG.pdf
If any more info or photos etc. would help then just say.