How to sell av equipment

I have some av equipment sitting in my spare room for the last year since I moved house, and I'm not going to use it again so I'd like to sell it. My problem is that I don't have the full set up or all the bits I need to fully test it actually works (speaker cables, speakers etc), which I'd like to do given that it's been transported then sat in storage for some time.

Specifically I have a Yamaha RXA680 along with a musiccast 100 subwoofer. I don't feel comfortable putting them on adverts.ie or whatever when I can't properly test them. Are there any shops that I could trade them into where they could ensure they work? Cex won't take them according to their website at least.