Violent and aggressive 4yo

[SailAwayWithMeHoney]

I want to start by saying DS is awaiting a reassessment for possible ASD. I think that's important.

Lately he's very very defiant, no matter what I say he'll do the exact opposite. He's very aggressive and lashes out violently.
Two nights ago he climbed over his baby gate and barricaded himself in my bedroom, locking the door before I could get in there. He only came out because he decided he wanted to get his shoes on and "go and live somewhere else" followed by shouting that he "will kill you mummy".
Seems like every day he's losing his temper (usually at being put for timeout for doing something he knows not to do) and lashing out at me, biting me, spitting in my face, pinching, punching, kicking, slapping, throwing things at me. He will do things he knows I don't like him doing. Bedtime is bloody horrendous where it never has been before. Suddenly he just will not go to bed. He will scream and throw a tantrum for up to 3 hours before finally succumbing and going to sleep. Usually a bedtime tantrum involves screaming, shouting, coming out of his room and locking himself in mine/bathroom, jumping on the floor (we live above a man) and smashing up his own things and trying to pull the babygate off.

I have HV coming out next week. But am wondering if anyone has any ideas? I really don't know what to do.

I'm removing all and any dvds of his that contain violence (just so that he's not seeing violence and aggression iykwim) and am trialling a new 'having his tablet for half hour at bedtime to chill'...
The tablet before bed is because he next to never has it and when he does it really chills him out, and I was literally at the end of my tether and could not handle another awful bedtime. I don't need to be told what a bad parenting move that one is

If he was previously calmer has there been something that might have triggered his behaviour? Any big changes? Sounds like he is letting off steam with you but probably about something else.
Is he at school? Might be exhaustion. Or if not in school might be boredom if he is high maintenance and needs lots of structured activities to keep him active. So he is lashing out because he has pent up energy.

He's on an off, he has phases where he's pretty calm and then (what feels like) weeks where he's like this. His routine has been very messed up what with Easter holidays and then the bank holiday and that does usually stress him out, he very much likes his routine.
He attends nursery 3 afternoons a week usually (barring holidays and things).

It's definitely possible he's bored, the weather has been vile here. But (probably should have added this in the OP) he is a runner, so taking him out can be quite stressful. A week or two ago he ran away from me and I lost him for 10 minutes, it took all my street to help me find him, he thought it was all a game

Oh Dixie bless you

DS is the same I think, the nursery say they have no problems with him at all
His old key worker was amazing, she'd tell me if he'd been aggressive or something but his new one is very much "your DS is perfect and never naughty!" Nursery was very unsupportive when DS had his 1st assessment.

I had a pecs (?) board that I was doing with him but he began to want to do everything "right now", for example I could put up clothes off, bath, dry body, pajamas on, brush teeth, toilet and bed and he would look at it, take his clothes off, spend 30 seconds in the bath, quickly dry, shove his pjs on, swish his toothbrush around his mouth, have a quick wee and want to go straight to bed. And he'd get upset if I tried to get him to slow down. And now he won't engage with it at all.
He won't engage with now and next at home either - but he reportedly does at nursery.

I think with bedtime he just would not allow himself to chill? For whatever reason he wouldn't wind down. It's only been 2 nights but the half hour on his tablet (in bed, lights down low) winds him down enough to then lay down and go straight to sleep. I don't expect it to last forever but it's fine for now.

I will have a look at that pathological demand avoidance - thank you so much

Everything you say makes so much sense. Tbh the more I talk to other people who've got kids (or siblings/nieces/nephews) with SN the more I think he probably does have some form of ASD

I'm glad your DS sounds as though he's getting some support (ie, not just at home) even if it could probably be better