Can you not sorn it?
How about strip it and scrap the rolling shell?
Have you put it on pistonheads? I sold mine there, took a month though and I'm in a high population area.
Also it's not a bad advert but why not copy out all the service history? It looks like you've looked after it so why not remove all doubt.
Also spend a day polishing, waxing, cleaning alloys and blacking the wheels - really go to town, then drive it somewhere nice (green fields go well against red) on a sunny day. Some 'artistic' shots really will help loosen somebodies wallet.
For the money you're asking and given the larger audience on pistonheads I'd be surprised if it didn't go.
I also used autotrader, cost me money and didn't get a single interest from it. Oh pistonheads gave me a premium ad for free, unsure why, maybe because I was a new member.