Hi guys, As the title suggests I have an early(G reg) W129 500 SL. It has covered 115,000 miles and has great history. Its taxed and MOT'd and in average condition(nothing major just a few scratchs.) I need shot quick and am going to trade it in over the next couple of weeks for a diesel. The question is what do you guys think is reasonable as a trade in value? I need to prepare myself for negotiations and could do with some advise. Cheers.