With regards to theatening rejection as leverage in negotiation, does this work? If I turned around and said I wanted to reject my car I bet my dealer would bite my arm off at the opportunity to sell it for £3k more to the next impatient can't be bothered to wait 4 months guy who walks through the door (regardless of lack of folding mirrors), let alone laying down a red carpet for me to make my demands. Does this threat work in practice?
Rejection is the route for a dealer that can't or won't rectify your issue. Has the dealer totally stonewalled you yet? If they won't do the remedial retrofit themselves and aren't willing to pay for another company to do it then it would appear that you certainly have grounds for rejection, under EU laws if not domestic Eire laws (although I suspect Eire laws would also protect the consumer against receiving an inferior/not to specification product).
To be honest, I would not entertain chasing quotes elsewhere for the retrofit and ask the dealership to pay the bill. You will have no warranty coverage on the retrofitted parts beyond replacement of the parts for 2 years (no labour coverage, it will not be seen as a part of the car you bought), and in the dealership system it could always be flagged as a mis-build, harming your future part ex value.
If they say they can't do it and don't offer an alternative then make moves for rejection. If they offer you money to keep the car, make sure that it more than covers a cost of a retrofit. Even if you intend on pocketing the money and living without, that is the minimum amount of money I would be looking for in recompense.
The longer you live with the issue, the harder it is to reject, but the time you brought it to their attention is taken into account.
At the end of the day, knowingly selling you a lesser car than the one you ordered and paid for, without making you aware of the mis-spec is fraud. They made you aware that the car spec didn't have folding mirrors as standard to cover up their cock-up - still fraud.
I would mention that if they laugh off your intent to reject. I'm sure the local papers would love to know that your dealership sold 4 people inferior spec cars for proper spec prices and tried to pass off the missing spec as something you needed to spec at additional cost, but didn't - maybe the other 3 are driving round oblivious to the issue you are currently facing because they believed the dealer lying to their face.
I would get in contact again, offering them a week to propose a solution and after that date, if you haven't heard from them or if they propose an unsuitable solution, you would be looking into starting rejection actions.
Speak to VW Ireland again publicly on Facebook - it's amazing how compliant they are when they have an audience of potential customers watching their responses.
