Selling old Whisky

Anyone got any experience selling old bottles of whisky. My mum has given me 11 bottles dating from late 70's and early 80's including some single malts. There is nothing particularly valuable but a quick search has shown that values seem to fluctuate wildly. So has anyone used a specialist auction site or sold directly to a dealer? If so, any recommendations?
Thanks for your help.
The single malts are:
5 * 75cl bottles of 15 yo Glenlivet (early 80's)
1 * 75.7cl bottle of 12 yo Inchgower (mid/late 70's)

And the blends are:
1 * 75.7cl bottle of Pinwinnie Royale Scotch (mid/late 70's)
1 * 75.7cl bottle of Johnnie Walker Black Label (mid/late 70's)
2 * 75.7cl bottle of Johnnie Walker Red Label (mid/late 70's)
1 * 70 cl bottle of Johnnie Walker Black Label (mid 90's).
And as an example of wildly different prices - seen the 1970's JW Red Label selling for about £35 at auction but a dealer has a bottle up for £150!