UEG

Hi, my dad wants to sell his immaculate "silver lady" he has loved since new (in 2000). Given PG valuations only goes far back as 2002, does anyone have any advice where he could go to obtain a realistic idea of how much she is currently worth? I remember talking to a colleague who was also a BMW owner about my fathers car many many years ago and him mentioning that particular model was highly regarded for its engine. I really don't want my dad to get ripped off by someone claiming it to be only worth a few hundred pounds given its age, irrespective of the ridiculously low mileage - and then find out it was actually worth a few thousand pounds and still a much sought after model. She came fully loaded with all the bells and whistles, full M-sports pack etc. Any help would be very much appreciated.