Spare Key Missing

Bought a >30k car last Friday from a main VW dealer in northside of Dublin. Its a 05 reg and when went to pick up I was only given one key. The second key was around someplace I was assured and would in fact be supplied. Since then despite numerous phone calls (by me), the key has not shown up and the excuses seem to change as to its whereabouts. The level of interest that they are showing in getting this resolved is hovering around the zero mark.

Where do I stand on this? If the key is missing can I insist on a lock replacement for the car or would people think its enough to allow them to reprogram a new blank key (which can be difficult with some of the newer cars I believe). Do I need to inform them in writing if I need to get a solicitor involved to get this sorted.

Any advice welcome!

I had this a few years back off a well known Dublin dealer, finally decided to request one in writing, they came back and said not problem at around £100.
Replied telling them a - second-hand - car should be supplied with two keys, I cc'd the head of the car company in Ireland.
Garage did not reply, however head of car company did saying he contacted the garage and I would have a key supplied at his - car company - expense.
Polite letter should do it, explaning the great reputation of VW etc etc

My car was a Renault, fair dues to Renault Ireland, having repurchased sine then I never go back to the garage though

A polite letter to the garage management initially should suffice.
Say you dont want to have to contact VW on the matter of the key, and that the issue could put you off buying there again, or endorsing them to friends.