[Closed] Nokia Lumia 810 screen repair while retaining warranty

As the title suggests really.

My son has dropped his phone cracking the screen, just the outer one.
I'd like to retain the warranty so I gather than means I must send it to a authorised Nokia repair agent but I also gather that's going to cost me about £130.

Just wanted to check that this was the normal approach or if I'm missing something. The phone is only from Christmas. I've look at Talk Talk's website and they say don't contact them, get in touch with Nokia. I presume I could get a normal repair shop to fix it but that would break the warranty.
Ta.