The UK agents for D-Link stated that as the item was not purchased in the UK, they did not support it. I guess that concurs with your findings in that as I bought in NY State, then I am bound and limited to US jurisdiction. Fair enough! Jeff
I can't speak for U.K. law specifically, but under U.S. law, if a foreign seller actively markets (i.e. advertises) their products in the buyer's jurisdiction, they are held to local law (even if the purchase was consummated elsewhere).
For example, Acme Inc., a foreign company, advertises in City X: "Residents of City X, visit our website and purchase our widget". The buyer in City X is making an foreign purchase prompted by the seller. Under these specific circumstances, the seller maintains liability. The real problem is enforcing those rights if the seller has no local presence.
Law on this is further modified by the conditions of the sale (i.e. the fine print), specifying the warranty conditions, sale location, etc.
In your case, it sounds like you visited a third party vendor website in the U.S. to consummate the purchase. The problem lies in the fact that you weren't directed there by "party in question" (not to mention that we're discussing U.S. law rather U.K. law.