To expect my working from home to be respected

It might be 'your home' but that only applies as long as your parents are willing to have you there. Nobody has a legal obligation to provide housing for a twentysomething child.

Your dad's being a bit of an arse but ultimately you don't have any leverage here since it's his office in his house - he has the power to be an arse if he chooses. You said you "contribute money to the house" but unless that's at least close to market rent then you really have nothing to stand on unfortunately. It sounds like the arrangement he agreed to with you living & working there has run on longer than expected and he's pushing you out.

1. Prioritize moving out. Find a place to rent that is within your budget even if you don't love it.
2. Take a hard look at whether you can feasibly work out of your bedroom on days you're WFH
3. Talk to your employer about working in the office 4-5 days per week in the short-term due to a temporary lack of private work space at home.
4. Actively manage your work schedule to put more sensitive calls on your in-office days
5. Acknowledge to your parents that you've been there longer than planned and you working out of the house regularly is an imposition. Offer to increase the amount you're contributing each month.

Also, who is actually charging their children market rent? Why are we saying oh well you're not paying market rent as if anyone should be. Of course she's not paying market rent. She's living with her parents not a landlord.

Working from home is great, but is not really viable unless you have your own home to work from. Why can't you go into the office?

I'm not saying your dad is in the right, and I WFH, so I get how annoying it must be. But you are living in his home, so I agree with those who say find a job where you don't have to WFH, or speak to your line manager and see if you can work in the office every day.

The trouble of using a "storage space" as an office is that now you need things you stored there.

I notice you say you make a financial contribution to the house...what form of contribution is this. Market Rent and split of bills or a token contribution to the weekly shop etc?

I suspect that your living costs are very being very heavily subsidised by your Dad /parents and it does sound unreasonable for you to start dictating which parts of the house he has paid for he is allowed to use.

By WFH people save commuting costs and the employer perhaps saves office costs but your dad is not benefitting is he?

Your options are like others have said is to use your bedroom, stop WFH and go to the office ,move out and start standing on your own 2 feet.

Just move to your bedroom. He surely doesn’t just burst in there?

He is right tho, it is his house
and your home.

And yet you're berating op? Why are you not pleased things are different?

I'm aware of that. It's unusual to be feel as strongly as her dad does that he can't just.... wait until her call ends.

Op is their child at the end of the day. He can be frustrated by it but there's absolutely no reason to act like such a twat. He can use his words to express his emotions like a grown up, and not act like an overgrown baby.

There isn't some weird rule that you must start acting like a tosser when your children turn 18.

No.
A different generation, born in a Communist country and usually out by the age of 20, due
to parental abuse, which was considered "normal".

It’s quite possible for people you love to be annoying, or for their lifestyle to negatively impact yours. She’s working - in a room that her DF has things in that he requires. How does it being a storage room mean it’s not disruptive to restrict access? People need things from where they’ve been stored.

OP is living in her parents’ place for her own benefit, not theirs.

I mean, she does. It's literally a storage room. Her dad is just being difficult. But I would say to use her bedroom anyway so he has no reason to come in.

It is more difficult if you don't have a space nobody else wants to use but unless you're on back to back calls literally all day, it's still doable with a bit of common sense.

Well it depends if you have an area in your house that nobody else wants to use. I don’t and obviously neither does op.

I had this crap with my parents. There was no happy medium. I glad I moved out when I did to get that freedom. Yes, I was paying a hell of a lot more, but had that freedom and peace. It will come.

Exactly. Only a nasty, spiteful person would behave as the dad is behaving. He has no respect or consideration for his adult daughter. Has he always been such a nasty and childish man @footballinthepub or is this something recent?

A different generation who enjoyed affordable housing and a completely different workplace environment?

I see.

Sounds like this is all new for your dad and he doesn’t like being bared from a room he uses.
so the quickest and easiest solutions are
Don’t work from home
or use your bedroom.

personally I’d chose to use the bedroom

Yes, possibly.
On the other hand, living at home with your parents at "mid twenties" isn't ideal, neither
is "working from home".
However, I'm a different generation.

Your father.. Jesus what a prick. He’s the man of the house and fuck you and your job. I’d expand my search to as far away from him as possible. Good luck flat hunting!

But her dad is the problem and OP has given him a solution he doesn’t want. He is actively deciding to be an arse and to not knock on the door before going in. OP isn’t suggest that he doesn’t disturb her at all, his asking that he knocks first.

I don't understand why some people have children.

Oh gorsh I must be super tolerant, i work from home pretty much full time in my bedroom, people come in and out as they please, thank goodness I dont put my camera on unless i really have to. Yes, it's really annoying especially when husband taking lunch time nap when I have meeting - he snores, so as my dog 😤

I really think you need to move out asap if this bothers you.

I found some comments of the strange. I think the concept of a family home is lost on someone people. It seems some people view their children as guest or strangers. I want my child to be happy and successful. I would be supporting my child if they were working, trying to build a career and saving up to buy a property. I would rather they save up than rent. It seems like the dad is trying to sabotage the daughter.

It's a shame, but for whatever reason, he's decided that he doesn't respect your work enough to knock. As so many have suggested, I'd start working in your bedroom, or if you know in advance when calls will come in, don't have too many calls in a day, and can easily move, just take calls there.

YANBU to wish your own father respected you enough to help you succeed in your career (by the simple, gracious act of not barging in without knocking first), but you can't change him. If this is who he is, you'll just have to work around his peculiarities and get out of there ASAP.