Flanker

Hello all. A quick question. I have a 1974 DT 175 Trail. It has 1200 miles on the clock and is un damaged , just dusty/dirty. I know that I must not offer the bike for sale here, but I do wish to find out how much it may be worth. Or how to find out its value. If anyone can help I would be very grateful. Thanks. F PS If this post is in breach of the rules, then I apologize, and moderator please remove this post.