I have an 8L S3 with the RNS-D sat nav which was retro-fitted by previous owner. However, I don't have the nav disk and don't intend to purchase when my Garmin is a better sat-nav anyway and I am having problems with it draining the battery, so it's coming out. What are my options, size wise, for replacement? I understand a Symphony will slot straight in but failing that how do I get back to a single or double din for an aftermarket unit as I can't find any fascia's for the 8L A3? If Symphony is going to be best/easiest bet, where can I get one from, apart from the obvious e-bay?