RE: charling lead faulty
They do go to great pains to point out the brick is for 'occasional' use only, so they could easily tell that the brick was being used to excess due to the internal timer. I also recall overhearing that as an accessory, it was warranted for 12 months only, and had nothing to do with the 4+ guarantee.
If the 13a plug is scorched, it sounds as though the socket it used was incapable of sustained 10a draw (the main reason they gave the warning). I carry mine in the bood for emergencies, but have never, ever used it - I've always had a T2 connection or a J1722 tethered lead to use.