At ScotlandWhisky we cannot, unfortunately, give valuations for rare or old bottles of Scotch Whisky. However, there are regular Whisky auctions in Scotland and professionals who, for a fee, will give you an accurate valuation of your bottles. The most famous Whisky auction house is Mctear's in Glasgow. Mctear's regularly sell rare bottles of single malt and blended Scotch. For the dates of their next Whisky auction follow this link: Mctear's Auctions
If you are unable to get to Mctear's you may wish to buy 'Collecting Malt Whisky: A price guide' by Martin Green. This is a good starting point for most Whiskies. Collecting Malt Whisky the Price guide