Delighted with my C5 2.0Hdi SX estated (build August 2003) owned from new since February 2004. Got this for 15K. Could probably have got it a bit cheaper, but I wanted the SX rather than the newer ones because of the greater comfort and cheaper tyres on this one (205,65 on 14" wheels). Got the colour I wanted too - silver and a factory fit alarm too. Now done nearly 10k and delighted with the car. Overall consumption creeping up towards 50 mpg. Had a drop in consumption a month ago and gave the garage some earache and booked it in for a service at 10k instead of 12.5k. However, just changed from Shell to Sainsbury's City Diesel which I vowed I never would try. Transformed the running. Consumption back up to 55 plus on a particular run done regularly. Had dropped to upper forties! Started to get engine rock too on cold start up which has cleared. I hardly believe this but it's true and I'm taking it up with Shell. I wonder whether it's possible to get a faulty batch of fuel. Consumption does drop to lower forties on a loaded French trip though.