DTM Renault Strand Sucks

Bought a Triber new in March. Had problems ever since. Shuddering clutch, grinding brakes, bad nose coming from engine bay when reversing and downshifting to 2nd gear, cabin fan not working. Had car back to dealer three times and they say that it is normal (except for fan which is on order). So, when we drive the courtesy model (same car and model) none of these problems occur. DTM then tells us that Renault head office has issued a statement that the noise coming from this Triber is normal and therefore they (DTM) cannot assist us any further. I asked the DTM manager why the courtesy car does not make those terrible sounds, he replied that it will probably still happen in future? We are being told that we must deal with the problem via Head office and they (DTM) cannot help even though we purchased the car from them.