Yeah, this. @FlyMeSomewhere If you do hold back that you have had a neighbour dispute, (and you have complained about them to the council and/or the police,) and the new buyer finds out, they can sue you. There will be records with the council, and the police.
We had fucking horrible neighbours some 25 years ago (when we lived in a 2 bed semi detached house.) They played loud music constantly, they screamed and shouted a lot, and they told us to fuck off when we asked them to turn the music down as our children couldn't sleep. (They turned it up very loud and went out from 7pm to 1am, 2-3 nights a week. Leaving the music blasting out.) When DH said he will report them to the police if they don't quit, the 'man' said he'll 'smash his face in' if we do that.
It was horrific, and it forced us to leave. 8 months we tolerated them before we put the house up for sale, and it sold within 3 days of the 'sale sign' going up. Luckily they weren't in when the first viewer who put the offer in came to see the house. The sale went through in 6 weeks as we moved into private let for a little while, whilst we looked for somewhere else to buy..
5 years we had lived there happily, when they moved in and destroyed our happiness there. But we never reported them to anyone. To be honest we didn't know we could report them to the council as we were homeowners. (And we were afraid to report them to the police after they threatened us.)
They were homeowners too, but they had made a massive profit on a 'right to buy' on the big sink estate 2 miles up the road, then tried to 'better' themselves by moving into a new build, in a cul-de-sac on a private estate. But they carried on with the sink estate behaviour sadly... Playing their music loud, threatening us, screaming and shouting, parking cars on the front lawn, and having 10-15 people around for parties and barbecues every weekend, til 4 in the morning...
As we never reported anything, we had nothing to declare fortunately. But if you have reported it you will need to declare it. Should we have told the new buyers? Yeah probably. But we didn't. We needed to get out of that house for the sake of our sanity, our mental health, and our childrens welfare. (As I said, they were struggling to sleep because of the noise/the loud music, as were we!) The woman who bought it was buying it to rent out as a private let property, so we wished and prayed that anyone who moved into it was an absolute cunt.