AIBU to be absolutely terrified of buying a house when I should be in a decent financial position?

I was also very anxious buying my last property. I think you are wise to think about liquidity; you can always make overpayments to the mortgage to help bring the loan to value ratio down but at your own pace. One of the best things I did in the end was to take a lodger - it pays more than half the mortgage each month and has allowed me to build up my savings as well as providing friendly company.

You are right to be cautious.

I keep thinking what if my business slows down, what if I stop earning as much

have you thought about the impact of AI on your business? Many small businesses are. Could AI reduce or eliminate your products and services? If not, then you have less to be concerned about. If so I would consider securing employment that isn't something AI will remove.

you need a role where AI enhances your productivity to give you some certainty of income at least for the first few years of your mortgage, and you can build your confidence and maybe trying to overpay for a year or too. As with everything there is more than one perspective on AI but it's not something to ignore.

Congratulations! I may have missed it but are you planning to invest the cash savings? If not, and your savings rate is lower than your mortgage, put more into the house deposit, or invest so you’re not losing out

You are making a great move for your long term future. Just wondering why you don’t pay down more of the equity from your savings to have a smaller monthly payment? If you paid off 100k you would have a mortgage of only 140k. If your self employment income was down for a time you could switch to interest only and it would be less than £600 per month (140k at 5% is £580).

It would also get you a lower mortgage rate as your loan to value ratio would be lower. You plan on borrowing 192k which is 80% of 240k but 140k is only 58%. I think a mortgage broker could get you a really good deal on that basis.
ETA you can currently get 4.99% for a 60% LTV mortgage from first direct fixed for three years.

When I bought my first house I almost willed the mortgage company to message me and say there's been a mistake and you can't have it so that I could just just put the silly notion behind me. I was convinced something would go wrong.

Genuinely, you will be fine! Congratulations.

have you been making pension provision too? It’s tax efficient, and, speaking as another self employed person, reassuring to know there’s some future income working away in the background. As long as you’ve got a year’s salary saved, you can afford to unclench a little - psychologically hard though it can be!

Would it be worth you looking into an offset mortgage.
You would need to investigate this throughly to see if it meets your needs.

Sounds like a good plan.

That's very dramatic! There is a middle ground between being destitute as a pensioner and rushing in to buy a house immediately.
I wouldn't be possible to buy now as a single parent at 21 with no savings. Times have changed and young people need to be far more considered in their decisions nowadays.

Good for you. I'm sure you have worked hard to build up your business. The earnings figures you gave were pretty misleading!
If I were you, I would put down more cash, as others have also suggested.

Do you want to be paying massive rent and risk homelessness as a pensioner? If the answer is no then buy a house asap.
I bought my own home at 21 as a single parent with no savings.
I havent paid any mortgage or rent in decades and saved all that money instead.
You home will always be your best investment.

Why are you keeping so much cash at your age. I would put a lot of your money into the house to reduce the mortgage and interest. I would start a good pension, have good income protection from illness, life assurance on the mortgage and mortgage protection and keep 30k ish for money you need in case of an emergency and focus on getting the mortgage paid. You will need to pay out so little money over a lifetime of a mortgage if the amount you draw down is the lowest it can practically be.

How am i fortunate? I haven’t inherited the money or been passed it.

Did you not know that other people can work very hard & make sensible financial decisions and still struggle to ever amass wealth enough to buy their own property? It's a thing, anyway.

Buying was hard for me because didn't like going into debt, I didn't like pinning my residence to one place for a long period, plus I am useless at interior decour or DIY, but facts are that buying is normally a good financial decision, even for someone self-employed like OP.

It’s a bit different when the OP has worked hard for the money and hasn’t been handed it on a plate.

I’m think your anxiety is causing you to make some bad financial decisions. How much interest will you make on the 100k you are keeping back compared to how much you’re paying on the mortgage? If the latter is more, then holding onto 100k just in case, is not sensible. Also, as someone else said, your loan to value will influence what interest rate you’ll get, so by scrimping on the deposit you’re paying even more interest to your mortgage provider. Your 35 year mortgage is also hair raising considering you’re only 30. Yet another way to give more interest to your mortgage provider. If you want to keep your payments affordable, put in more deposit.

You say in your panic you’ve looked at how you’d get by living on your savings. In a nuclear scenario you could always sell your property. You aren’t locked in for life. If you’re sensible you’ll make sure the property you purchase is desirable enough, ie not next to a train track, no bus stop directly outside your front door, not opposite a noisy playground, near enough to transport, if a flat, no bananas service charges, long enough lease etc…

You’ve obviously worked hard to save the money you have, make it work for you. If you are keeping a lot of money back, worth knowing that Martin Lewis recently demonstrated how those who invest some in shares do better than those who put it all in fixed interest rate accounts. I wish someone had told me this at 30.

I do also think that people quoting that your rent/mortgage should be a 1/3 of your salary have absolutely no idea how expensive it is to rent/pay a mortgage at the moment.

Just do it. You have a decent buffer if work slows down. If there is a recession interest rates will fall through the floor anyway. If your business slows down you can find a regular job. The earlier you get in the market the better because it is simply time in the market rather than timing the market that builds capital.

Housing values can fluctuate and stall but generally go up over time. Also it's the only capital purchase you will make that you can also live in! My first purchase was 240k at 24, my most recent 1.04 mil which has now appreciated to 1.7. If you can put even more of that deposit into a slightly nicer property I would do it. It's supply and demand that causes price increase (inflation) so the area you buy in is critical. It has to have what alot of people want or might want in the future.

But you bought in the mid 1990s, the best time for anyone to buy in recent memory! That was purely based on luck at being born in a certain year.
If the OP buys now, she is likely be looking at a depreciating asset for some years, at least, as the market is falling in many areas. We can't assume that houses will continue to rise at 4/5% every year (less in real terms) just because they did in the last 30 years.
I'm not saying that @BeQuaintLion should not buy but she should not buy assuming that it will be a great financial investment just because some other people were fortunate.
@BeQuaintLion , can I ask why you want to take such a long term if you are buying in your mid 30s? You could shorten this and waste less money on interest? If it's not cheeky, can I ask how you managed to save up so much? It seems like a lot of money to have saved on your salary? Are you renting or living with family? You don't have to answer, obviously, but it may be worth thinking about these things before you make your decision.