God, I completely get why you wouldn't want to post a link. People can be such assholes. Plus, y'know, then everyone here will know where you live and potentially who you are. Nothing hard to understand about that.
As for why it isn't selling, I think there are a few things. Firstly, it sounds like you're in the middle of a fairly long chain, which may be unavoidable because of the kind of price range you're occupying. But it does mean that you're more at the mercy of everyone else's problems.
Also, if you're likely to be in a long-ish chain, I think it's extra important to be very flexible about dates and logistics, and generally make it easier for everyone else to be accommodated, so make sure you're not fucking things up by being very b&w about that kind of thing, be prepared to move into rented temporarily in order to secure your sale, for instance, and also be as sure as you can that your solicitor isn't being an asshole to everyone else's.
In terms of the market, I think that Brexit uncertainty may be particularly affecting FTBs, who are having to raise a stupendous amount of money just to get on the ladder in most places and who are therefore the most susceptible to ideas about the possibility of prices plunging if they wait a bit. If the problem is mainly your buyers' buyers, this might be the issue. Not much you can do about that, except try and pitch to cash buyers or FTBs with vast resources, which may mean rethinking your price following advice from someone who really understands the market.
Finally, I'm wondering about your agent. Did the people over the road use the same agent or a different one? My only experience of this kind of situation isn't current, so may not be relevant, but I was once involved in a house move that took a stonking 12 collapsed chains to accomplish. We were about ready to die of the stress by the time it went through. LIke you, the problem wasn't the property we were selling, which sold easily - again and again and again. But we kept losing buyers and every time we did, we'd lose our purchase too. The market was a bit overheated and the agent, I now know, was playing buyers off against each other, trying to get people to offer over the odds and gazump each other, in order to push their commission up. They were also trying to get people to sell through them too, in order to have a shot at buying the house they wanted. And much else besides. It was very sharp practice, but we had no idea until a spurned buyer knocked on the door and told us how the agent had treated them. I think that kind of marketing can lead to shaky chains, as people offer through the nose to get the house they really want but then have weeks to rethink whether they've made a good deal or not. So maybe think about that and ask yourself whether the agent's really acting in your best interests. We changed agents from a pushy, top buck type to a low key family firm and the next chain held.
I hope your luck improves. I know how abysmally stressful this must be.