This subject has been on my mind recently, too. I work for a company that supplies JLP and have recently noticed that they are no longer so insistent on customer service. The customers have been ringing us directly and e-mailing us and I have been passing on their complaints to John Lewis to get them to set up an order on the complaints system so that I can do something about it and not hearing back from them (We have no way of processing orders directly from private individuals - that's John Lewis' job).
It's almost impossible to find a telephone number to get in touch with them.
One of the customers mentioned that she, too, had noticed a deterioration in the service of late.
This must be the beginning of the end, if even John Lewis are outsourcing their customer service and becoming more impersonal and less helpful.
My mother, however, is very satisfied with their service, and uses their website a lot. She recently ruined her ceramic hob, which was an unusual size, and JL were very good about delivering and fitting a replacement.