Are DPFs covered by warranties, and how best can I store winter tyres when not being used?

Are DPFs covered under manufacturers' warranties? Would they be covered under wear and tear cover from third party warranties? Also, do you know of any wheel nuts that don't rust? I thought tyres needed...

The write stuff - winter tyres

As you may have guessed I can be a persistent individual. After our protracted correspondence, I would like to let you know that the Prudential Insurance Company has finally agreed that its stance on fitting...