About half that price at Coastal Motorhomes I believe, if you buy the bare lamp unit without the LED driver. Just have to swap the driver over from your old lamp to the new one, unless it's your LED driver that's packed up. It seems that the RH lamp is out of stock at the moment, but CM may be able to give you some idea of a restocking time.
New Right Hand Drive Right Headlight With DRL Black Housing. Fiat Ducato, Peugeot Boxer And Citroen Relay From 04.14 Onwards Face Lift Model. Does Not Include LED Driver You Will Need To Swap This From Your Old Headlamp Or Purchase A New One. Please Check Our Photos, Part Numbers And...
Part numbers can also change when a component is revised or obtained from an alternative supplier. A revision would mean that the part is a replacement for the original which is no longer available other than from unsold stock. Coastal Motorhomes would probably be able to answer as I believe they have access to the current Fiat parts catalogue. Alternatively you could try a Fiat dealer but you may find them less helpful.