Spec and mileage have a huge influence: SE models with leather upholstery and air con are liked; base models without extras are not. A 99V 520i SE with 28,000 miles is just under £15k at a non- franchised dealer. Even more desirable is a 523i SE with leather and climate control; a 30,000-mile 99V example is about £18k at an independent specialist.
A sportier alternative is the 193bhp 528i - around £19k buys a 00W 20,000-miler. And for family load-lugging, Touring estates start at about £11k for a tidy 1997 520i SE.