The contract of warranty on your Naim equipment is made between you and the reseller. In the UK it is then usually underwritten by Naim with the following terms;
Demonstration-stock units are slightly different in that the 2 year warranty clock starts ticking the day the item is shipped to the retailer - these units are not eligible for the extended 5 years warranty. Any of the 2 years that is left to run when the retailer sells the demo unit on is transferred, but can not be extended.
Warranty for Graded or Naim Refurbished stock - Mu-so and Mu-so Qb = 1 year; Everything else = 2 years
Note that resellers may offer their own warranty with different or extended terms outside of those underwritten by Naim. Also, warranty terms may well differ in different countries. For details of these please contact your local Naim distributor.