if its any consolation the speakers are about £18 a peice from VW so not going to break the bank if it screwed, my guess its around the door gromit area, sometimes wires can snag and then get pulled and frayed when the doors are opened and closed. Pug 306s were renowned for this (all the 3dr wiring into the doors was about 2-3mm too short in the factory and they wore thin with age and split, lol)