Really at the end of my teather!

That sounds horrible for you OP. They sound totally dreadful and I'm so sorry they are putting such a miserable cloud over what should be a happy new start for you and your young son.

It sounds as though your son and you are making new friends there enough to have a party. Could you speak to the people whose children came to the party and your other neighbours to see if other people have problems with these foul neighbours? If you know it's not just you then it won't feel so personal and perhaps other people might have ideas of how you can deal with them? Maybe they all have trouble with them and you can stand together against them.

I've found that there are always gits like this in villages, people who try to ruin it for other people and who are against 'new people' coming in. I know it's hard, but don't let them spoil your new start.

They should be training, and taking responsibility for their dogs.

As suggested, keep a diary of every event. Record any aggression as evidence. Ignore them shouting, and if you’re having kids over to play, turn up your music to drown them out. Instruct your son not to speak to them. If they shout shut up or FO, smile and say “No”. Have the council given you any instructions on how to move forward with a complaint? What they’re doing also constitutes harassment, which the police can deal with. Consider contacting them for support also.

You poor thing. I’ve had this and it was horrible. So oppressive. So hard for you to relax in your own home. We moved, which I know might not be an option for you. I really appreciate the difference it has made though.

YANBU, sorry I accidentally clicked YABU. They sound like utterly awful neighbours. Distance yourself from them.

Ignore, ignore, ignore!
Guide your son not to interact with them. He simply needs to turn & walk indoors.

Do not do anything to inflame the situation and keep a diary of any interference.

You sound like an ideal neighbour.
What you’re going regarding bins etc is nothing to do with those nutters. You could report them for harassment.
Sending a supportive hug.

Tell them to never knock at your door again, and to never, EVER, interrogate your son about anything, ever. I would be raging about that if I were you. Tell them to leave you the hell alone.

Have you got a fence OP?

They will be like sharks smelling blood if you give them too much leeway and act too nice.
Now is the time to set boundaries. If someone was interrogating my child in his own garden, I'd be over there like a shot and they would feel the sharp edge of my tongue!
Seriously, you need to shut down petty complaints / they'll never be happy. As soon as you solve one problem, they'll find something else to carp about.
Stop being so friendly and start pleasing yourself and ignoring their moans - literally nothing you are doing is unreasonable.

The complaints are ...rain water running into their garden.... not my problem

I am taking my bins out to early/ bringing them in too late on bin day not your business

a 'squeaky front gate' gets them complaining! wd40 will fix

young son playing quietly in back garden with his dinosaur models as they say he sets their dog off barking 😀
not your business, not my problem
Me putting washing out as it blocks their veiw and sets their dog off barking.
not my problem
Me and my son sitting talking in our garden whilst we eat a packed lunch ,as it also sets their dog off barking!
not my problem

and this... not your business
The neighbour (Woman) called him over and really quizzed him on:
1/ where was his dad?
2/ why did we not live with him?
3/ where did I work?
4/ both our full names.
5/ where were we from originally?
6/ Why is he setting her dog off barking?

I'm afraid I'd be knocking on and telling them what I do in my property bounds is none of their business, their dog barking is their problem - not mine. However them approaching my son and asking intimate details about our life is a very big problem, they do not do that again.

Don't leave this chat too long, set the boundary early, very early.

Yes, total arsehats im afriad
They won't change, but I'd get your son to nip inside for a few minutes if she questions him, he doesn't have to talk to her, she's very rude. You should be able to enjoy your garden if you're not being too loud, which it doesn't sound as if you are.

Ignore her.

They are nutters, pure and simple. They should NOT be interrogating your son like that. Sorry you're having to put up with this.