Age/Value of Highland Queen Grand 15?

[murray88]

My grandad passed away recently and despite the fact he didn't drink, he had a great deal of Whiskey he had collected over the years that people had given to him either as Christmas presents, or in the case of the bottle I have, a gift from a company he worked for around 30 years ago. So I was wondering if anyone could help with in regards to finding out how old it actually is (the 30 years thing could be wrong, might have confused it with another bottle or something), and how much it might be worth. Thanks .