Its at times like this I would worry about the warranty not being honoured, best of luck
I'd agree you really need to think of the possibilities well in advance when you do something like this.
Consider what just happened to me. Last Monday my car refused to start when I left work. Not the sort of thing you immediately think is major, but the RAC couldn't get it going so towed me to my local garage. That's where I get the servicing done, and it's not a dealer. The garage phoned the next day to say it was a catastrophic fail, and a warranty job, and would have to go to a dealer.
As it happens, my car isn't mapped and there was nothing (well not much) to hide, and I arranged for it to be taken to the dealer I bought it from, 25 miles away. I'm sitting here waiting for a call from them to tell me I can come and pick the car up, after they've done the final checks on its NEW ENGINE.
The last time I saw the car was when I walked away from the local garage towards my house, over ten days ago. The rest of it was all done by remote control, as it were. If there had been a map on that car, trying to get everything back to original spec before VW got it might have been possible, but it would have been a major headache.
Even as it was, I was terrified VW were going to find some way to repudiate the warranty, because the car had been serviced by a non-dealer. For example, purely hypothetically, if the garage owner had happened to fit a non-branded air filter at its last service three weeks previously (because he couldn't get hold of a branded one), and that was on the invoice he'd given me, he'd have had to alter the invoice to make it look as if a branded one had been fitted. Or else VW would have repudiated the warranty even though the failure had nothing to do with the air filter. Or so I believe. Entirely hypothetically you understand.
Even as it was, the local dealer was repeatedly harassed for every minute detail of everything he'd ever put into that car, including having to provide proof of purchase of the branded VW long-life engine oil. He obviously satisfied them, since VW are now playing nice and the new engine is being fitted under warranty. However, it's scary. I dread to think what the bill for that would have been if they'd found some way to wiggle out. And that's without anything as off-the-wall as a remap. (And by the way, they refused point blank to give me a courtesy car, due to the non-dealer service, and as I was all booked to go on holiday with it, I had to hire a car at my own expense.)
So all I'm saying is, don't assume every encounter your car has with VW can be pre-planned and prepared for. You too might find yourself stranded in nowheresville with a buggered engine, and limited opportunities for making sure everything is presented to VW as it should be.
