Still trying aren't you?
E1/Zero-B Cockers go for £150-£180 generally. That's the reason you're struggling to sell.
I know it's crap but if you want to sell you have to bite the bullet, not flood the forums, I have done several times and it's a p!sser.
Tank =£50
Hopper =£70
That leaves £255 for a £155 marker.
Sorry to break it to ya