85 watt L-type connection fault.

My 85w L-type power lead to my 15" MBP has started to fray. The fray extends 3 inches from the connector and the metal braid is showing. Surely this shouldn't have happened. The charging still works and the LED's function correctly. To me the outer covering is of inferior quality and I wondered if anybody else has experience this. I took the lead into my local Apple shop but they just stated it was wear and tear - not very helpful. I guess I will have to shell out £65.00 for a new one.