Having just read the Nikon website on the subject it suggests what I was expecting anyway.
My understanding has been that UK consumer law always says your issue is always with the place you purchased it from. Doesn't matter how long or the type of warranty the OEM offers.
So for a Grey item it is covered by Nikon warranty, in the country it was purchased in… So if it goes wrong the seller needs to take it back and return it to the place it was bought from (Hong Kong? ) and has it repaired locally and returned to you after.
In all cases your dispute is with the seller not the OEM, even UK items you would take back to the seller and agree a resolution. Where by the UK seller could well return it to the official Nikon centre, as the Seller is having it fixed under warranty not the buyer.
So the issue or risk then becomes, is the seller still in business to support, how long you have to wait for a repair.
I'll take the risk on new D7200 shortly