Pity you don't tell us what age the car is, so I will guess that it's a classic car which might origionally have had a valuable registration number. If so this has been sold by a previous owner and DVLA have issued the car with an age related replacement number. If this has been done the new age related number is not transferable to another vehilce therefore no matter how attractive it would have been to a number plate dealer it has no value owing to the fact that it cannot be transferred. The true value of the CAR should not be effected by this, however if a prospective buyer was looking for a classic car with a valuable number plate he would not be interested in buying this particular vehicle. So there could be a circumstance where the perceived value of the car is reduced by virtue of the fact that the number plate has no value. A true enthusiast for the car in question should not however be put off by this if he is interested in the car for what it is in its own right.