I have sympathy for your correspondent RM of Worthing (DT Motoring Saturday 9 January) who is waiting for an ABS sensor. I feel you could explain why main dealers, who do not have the spare that would put a customer's car on the road again, take so long to obtain the item required. To order on the guaranteed 3-day delivery that most manufacturers claim is available, the order has to be placed in the Vehicle Off Road system. The dealer then receives the parts priced at 90% of the list price, giving only a 10% mark up. If however the part is processed in the normal way with perhaps delivery occurring two or three weeks later the mark up will be 100% giving a profit of 50%. This is the way manufacturers encourage that dealers to maintain a reasonable stock of replacement parts. In the past where a dealer has stated that parts supply is very bad for a critical item and the part will take two to three weeks to appear I have asked for the VOR number of the order. Hey Presto after much scurrying around a number is given and the parts appear in three days. This was particularly applicable to expensive parts with the full profit at risk to the dealer. The present system may be different but I doubt it.