Thanks for this James08, FWIW I changed the oil and filter myself last weekend, and it became obvious that it hasn't been done recently (under tray bolts corroded in, filter very much attached - ie: no lubricant left on the seal). The oil level warning still appears sometimes, and seems to correspond to the angle of parking and where the sensor dips into the sump (front, nearside). PS: I must thank whoever posted the link to service.citroen.com recently hereabouts, the parts diagrams are excellent!