Whilst I am certainly not going to enter into the merits of any particular warranty claim (other than one which may involve me) this whole issue got me a bit curious and I have done some research on the subject. I'm not going to claim to be an expert but I have found some information purely by chance as I was searching for something else.
The following is translated from an Italian information document on the registration of imported vehicles: "In the case of defects in the functioning of an article properly purchased, the consumer may take advantage the legal guarantee of conformity, the period of which is established by the directive UE 44/1999 and is equal to 2 years in all European countries. The right of guarantee can be exercised directly with the seller."
I have found some similar references in English but this referred directly to motor vehicles. The seller in this case refers to the dealer.
The document also states that it may be difficult to make claims internationally as the dealer is not obliged to pay transport costs of the vehicle or pay for repairs carried out by a third party. It goes on to recommend establishing an agreement in writing before having any other workshop carry out repairs.
It then goes on to state that the so called Manufacturers Guarantee is not governed by EU law and may have various restrictions and limits. This guarantee would normally cover repairs done by authorised dealerships Europe wide but may not necessarily cover certain items and is viewed as a separate contract agreed between the parties. Read your warranty document carefully.
The only item that can not be restricted under other EU legislation governing the restriction of competition is the right to have any competent workshop carry out servicing.
You can draw your own conclusions but it seems to me that the actual dealer carries the greater legal responsibility for the guarantee under EU law it is then up to him to take it up with the manufacturer. Not a very fair situation for the dealer.