Make sure that you check your products before you purchase it, especially from Amazon. This is on the Nikon Cashback website:
Info on non-EEA products
Nikon Cashback promotions are not available on Non EEA products.
As a trusted and respected brand it is important that Nikon customers can be confident their products will be supplied with valid EEA warranties, correct power cables, English manuals and that they will receive the quality of service and after sales support that Nikon is known for.
A number of retailers offer genuine Nikon product from outside the European market for sales to customers in the UK. Nikon UK cannot guarantee that these products will be supplied with a UK power cord and adaptor which meets our quality standard, or that the customer will receive an original English manual or a genuine European warranty card. Because these products are not intended by Nikon for the European market, they are not eligible for UK promotions, including our cash back offers.
To ensure you purchase product intended for the UK market, please refer to the ‘where to buy’ pages on the Nikon website.