I have inherited a pair of Wharfdale W90 speakers in very good condition, but not being much of an audiophile I don't know much more about them except that they're a classic 1960's design, great full sound, very heavy sand filled laminated beautiful mahogany wood cabinet design. They're too large for my current place and I'd like to sell them. Does anyone know if there is a demand for classics like these? How do I find out what they're worth?