Passat aircon warranty problem

I've a 161 passat. It was a late reg so it's just over 2 years old. I've owned for 18 months bought from local dealer.

In the first bout of hot weather, I noticed that air con was gone. I rang vw local dealer as it's under the three year manufacturers warranty. They took it in straight away and the checked it over. Sure enough gas gone. So they rang me when car was in the workshop. Re gas €120. Not a warranty issue. Needless to say I was a bit annoyed such a new car needed regas. I've had a corolla and a golf that needed regassing after 6-7 years. But I wanted aircon. They assured me they did a "leak test" as part of re gas. I had been reading that if you don't use aircon much, a recharge after 2 years is likely on a few forums, so I accepted and I ponies up. At the same time I booked it in for service that was falling due end of June.

All was good for about 2 weeks. Definitely noticed it not being as effective after that, until eventually no more cold air at all after about 4 weeks. It went through the service and some coolant piping was seeping so it had to go in for another day at start of July and they'd look at aircon this day as well. Apparently they only do servicing when servicing...

Anyway in I go for third day in 3 months. This time they tell me theres a problem with the air con radiator. There's a lead time on the part so it'll be end of July. I talk to lady on desk about getting my 120 back for re gas. I firm no, but she did explain who I need to escalate to. So I've to take that call tomorrow.

I know re charge are wear and tear. However I feel the first leak test was not through enough - it's unlikely or/and unlucky the leaky radiator developed after the regas. So my view is it's a warranty issue and I want my 120 back. What are my chances? How far will I have to take it?

Also it's a pity I'm visiting the garage so often!