So pleased you have had a good experience at your local Nissan Centre.
I think over the last 18 month Nissan have really tried to bring the network in to line a bit, with the "Nissan Care 4U" initiative, seems to be working well, so far, but time will tell ultimately. The good news is that there is now more opportunities for centres to earn extra cash on CSI bonuses for getting it right!
I have never understood why warranty issues should be so hard to administer from a dealership point of view, its money for old rope TBH and a great money spinner for the centre as the money is paid directly to them from NMGB at a good labour rate!? Therefore in theory the only issue with some warranty claims is Nissans willingness to cover the issue as part of their T's & C's