TBH splitting up a large collection is the way to go.
You'll get the most interest and the best prices.
Amibay is an alternative to eBay, no listing or final value fees and a good community. Although it is NOT an auction site and you will have to have an idea of what you want for each item and state that.
Selling in a job lot will mean you have to sell at a bargain price to account for a local pick up and as long as you're not too remote this shouldn't be a problem. Although if it does go in one go then there's no messing about trying to shift hard to move items (like the magazines).
You could always try to donate them to one of the online Amiga projects (
Classicamiga being an example.)
