DH's inability to leave me alone!

He is not 'being nice'.

He is 1) being controlling and 2) trying to gaslight you into feeling you're being the unreasonable one.

He is not 'highly strung'.

He believes his way is the the right way and your feedback = the domestic appliance malfunctioning. Which is not acceptable. And therefore throwing a strop should stop you doing that.

So you start to avoid anything that could be a stroptrigger. Including saying how you feel. See how that works?

If he knew that you disliked scrambled eggs, but made you scrambled eggs for breakfast every day, that would not be a nice thing to do.

This behaviour is the same. It's not nice if he knows you don't like it and he keeps doing it.

I just start doing it to him.

set a vibrating timer for every 20 minutes. And do it for a week. And If he says anything feign ignorance.

it’s would drive me mad. Either come and bloody find me if you want to actually tell me something or you don’t, then leave me alone.

and when he wanders of and doesn’t respond call him on his phone ask where he’s got to.

and as a rule add an extra 10 minutes to what your doing whenever he asks. He’s being so annoying

All of this.

I imposed a rule that no-one was allowed to talk to me unless they were in the same room. Yelling for somebody should be an absolute last resort tacked onto the end of a sentence like "the house is on fire".
And do this. Ignore every time.

He’s not being nice. That is rubbish it is because he wants you to do something for him or kids. He doesn’t want you to be able to control your own time. That ISN’T nice at all.
My DH sometimes texts me similar. Maybe once a year. It’s because he really thought I was popping out for a couple hours with the dogs and I’ve been all day. He honestly is concerned that I’ve somehow hurt myself walking two giant hounds. (I have form for this. Not just once either!) But in the house? I’m an adult who can be trusted to shower or read a book without coming to serious harm.

He’s not being nice. That is rubbish it is because he wants you to do something for him or kids. He doesn’t want you to be able to control your own time. That ISN’T nice at all.
My DH sometimes texts me similar. Maybe once a year. It’s because he really thought I was popping out for a couple hours with the dogs and I’ve been all day. He honestly is concerned that I’ve somehow hurt myself walking two giant hounds. (I have form for this. Not just once either!) But in the house? I’m an adult who can be trusted to shower or read a book without coming to serious harm.

Same problem here! Its irritating and I worry what will happen when we retire and are around the house together a lot more. I think its because he is more extrovert and likes to know where I am so he can come and talk to me if he gets the urge. If he's bored he follows me around the house talking to me. That man will need some hobbies!

When I've called him on it in the past, he gets offended
This is a strategy to make you stop calling him out.

I don't want to have to tell him where I'm going and how long I'm going to be around the house! He doesn't do that for me.
You are the default parent, so he sees no need to tell you where he is. It is not his job to think about 'who would look after the baby if we both decided to go work in the shed/garage'. He assumes he can just go, but you can't.

I'd be really surprised if that was it
It is it. He is 'highly strung' because he doesn't think he should have to cope with being left alone with the children for too long. He makes a fuss as part of training you not to expect too much of him.
He likely does not even consciously realise this is what he is doing. These behaviours can be subconscious, learnt from the dynamics between his parents.

The answer is to increase the time you take for yourself, not decrease it.
Tell him you are going for a walk to get some exercise and clear your head, and will be turning your phone off for a couple of hours.
Then follow through and actually do it, regularly.

This. This is genius. Adopted.

I’d shout back “No! I’m dead!”

I used to have a live-in partner who did similar things. He was controlling.

For example, if I went for a bath, he would want to know why I was taking so long under the guise of concern. Ditto if I went to the Sainsbury's around the corner from our flat, I'd get a phone call asking why I wasn't back yet. His control seeped into other areas, but these were part of a pattern of behaviours - annoying and infantilizing.

I suspect he may be controlling in other aspects of your life, if indeed this isn't to do with him wanting you to return to your default parent duties.

@Ihaveneedofwaternear this would drive me nuts. I remember a novel years ago where the woman said her marriage was like a giant game of ‘May I?’ as she couldn’t just go elsewhere in the house without telling her partner. It’s stuck with me because it would irritate the hell out of me!

Shout back that you're busy sexting your lovers.

It's because parenting is your job.

Paying attention to him is also your job.

Paying attention to yourself? Not what correctly functioning domestic appliances do.

Therefore you're neglecting your job.

The shouting is his exasperated way of telling you that you are malfunctioning. And that you need to get your arse back down stairs now.

So you need to make VERY clear statements and repeat them, like you would a child.

I am going for a shower and a face pack and a mani. I will be xx minutes and back down in time for House of Games. I will be fine.

Yes, I am ok and don't need supervising and checking in on when I'm trying to shave my legs and not cut myself.

Shouting at me when the electric toothbrush is drowning you out is pointless. Listen for the sound of the brush.

I do not like it when you shout at me up the stairs. Stop doing it.

On repeat.

In my experience that is exactly what it is. Tell him to stop. If you’re always sloping off for ages he would be justified in asking - but he should use his words properly and ask if you could come and help him with whatever needs doing, not ask if you’re ok, for crying out loud.

New family rule: you can only talk to people in the same room as you.

Then he will have to come and find you in the bathroom, see you brushing your teeth and ask you what you're doing.

I'd answer with a question every time "why do you ask?" or "are you ok?".

My DH does this, more so when DD was younger. Drives me mad. It does feel like a subtle “Come back and pay me / our child attention”, like you’re being lazy and neglecting your job. Worst time when when I was on the loo for a while and I’d hear “Let’s go find mummy”. Made me rage.

Have you asked him? I’d guess anxiety too, whether it’s anxiety about parenting or not having you around. If he doesn’t do it when it’s just the two of you, have you asked him why? Maybe it’s because he feels like he’s got your full attention? Whatever it is, it’s not going to change unless you share how it’s making you feel (stressed, irritated, angry, whatever), and point him back to himself to sort whatever is driving him.

You mentioned DS? Is he baby? Is your husband pestering you because he wants you back in the room looking after little one? My husband was a bit like that because he stressed so much about the baby starting to cry and him not knowing what to do 🙄

I agree with this.

Whatever the underlying reason is that he is shouting for you when you are out of sight, he is interrupting what you are doing. As in "stop what you are doing right now so that you can pay attention to me". You can't be doing anything, at that moment, that he can perceive of as being more important than paying attention.to him.

It is also rude to "summon" someone like this by yelling, expecting them to make the effort to respond to you yelling for their attention, instead of you making the effort go to them. ( Which, in your case, would be even more annoying....)

Try "fuck off, I'm busy" next time, if he can't rein himself in.

So don't say anything, reply nicely but give him a job to do every time this happens. Eg

'Are you all right, you've been up there for ages'
'Yes fine thanks! Could you start unloading the dishwasher please!'

Assume he's not busy if asking so find him something to do.

Next time. Just tell him you need some time alone (whether doing anything useful or not) for your mental health.

The OP has already said he doesn’t do it if it’s just him and her in the building.

I live with people like this and it's so infantilising.

I would be telling him in no uncertain terms that you do not want to be shouted at or for, and those are your boundaries.

Only people who can't respect your boundaries will be cross you're trying to assert them and that's a them problem.