Have I f*up my finances?

I think you should rule out investments until you are confident.

Based on this the lowest risk is probably;

Step 1 - now
Look on a comparison website such as money supermarket for a cash ISA with a rate greater than your mortgage rate. Look for one that does digital opening so you can open before end of tax year (this week) be sure you note any conditions about withdrawing money and dont invest if you feel you will need this money.

Step 2 - tomorrow
Speak to your mortgage lender and see how much you can repay as an overpayment without an early repayment charge. Pay this back. Also ask them what date counts as next year from an overpayment perspective.

Step 3 - tomorrow
If you have an amount you could not repay from step 2 open the cash ISA identited in step 1 and move 20k maximum to it. If you have more than 20k then ideally do this before Friday (tax year end) and then next week move another up to 20k (next tax year).

Step 4 - next week
Any remainder (over the 40k in the ISA) put in a high rate savings account - remember you will pay 49% tax in any interest.

Step 5 - seek advice
You have now mitigated your risks and can seek advice on investments if you want. Learn plan and invest when comfortable. Bear in mind any conditions around ISA withdraws and penalties.

If you just want out then when. Your mortgage allows next overpayment without an early repayment charges then take money from ISA and repay this.

If you have never been a landlord before then don't start now.

Most landlords are selling up including us.

It is just not worth it any more.

I would just pay the money back to the bank unless you can get more interest investing it than the mortgage rate, which I doubt you can.

Overpay on your own mortgage dep on the rate, and/or pay into a Cash or S&S ISA. Or into a pension. You need to make your earnings, savings & investments as tax efficient as possible.

Do you have any savings vehicles for your children?

You will be able to cancel. Push them and say you took wrong advice and your home is a priority.

Someone set out above - immediately pay back 10% if allowed repayments. Invest remainder in Vanguard or Interactive Investor - they charge a flat fee. Put it into a stocks and shares ISA into a blended fund. Vanguard have 80% equity funds that give excellent returns and you have 25 years until retirement so can take the risk. Pay off the max amount until all the money is back in the mortgage.

But you're a higher rate taxpayer, so these things would need extra thinking about.

Don't do / take it and just save more money away monthly for now.

Keeping a safe roof over your head should be a priority. Cancel the mortgage withdrawal.

Start to save separately into a stocks and shares ISA. Choose a whole market fund. Watch your money grow tax free with better returns that in a Midlands property.

No one with sense would borrow half their equity to take a risk in a market they don’t know much about. You’re putting your home at risk.

Speak to a financial advisor.

This is sound advice.

Return the money. It's risky having all your net worth tied up in illiquid assets if you need access to funds. Plus transaction fees are high so if you need to sell a property in an emergency you could end up losing money. If you have a separate emergency fund or cash savings it might be different.

Other options are all a risk.

It could be that stock markets soar after world events play out , or there could be a major crash.

Same with gold crypto or anything else.

Read up, pay someone to financially advise (not take a percentage fee) and look for funds with low fees

Have you signed the mortgage?

If you really can’t pull out can you overpay some of it back? Normally you can do up to 10%, so that’s 20k. Then you could put the rest in a high interest ISA using up your allowance.

if you can’t figure it out, seek independent financial advice.

If you don’t have the money yet, don’t take it. You’ll be hard pressed to find an investment that will be worth more than the saving in your mortgage as I assume it will be at 4%+ and the amount is too high to be put into an ISA.

you need to stop scrambling and sit down and do the math of each of your ideas. No one on here can work it out for you. Or speak to an independent financial advisor. It’s a lot to take out £50k of debt with no clue of what to do with it.

Please don’t.

Just focus on paying off your mortgage. The end

and anything spare… pension or savings for your kids

Also last tax day for ISA is Sunday if you act very fast you can move 20k before then , and another 20k next week as it is next tax year.

ALWAYS read conditions - some have lock in periods and you will be unable to withdraw interest without a big penalty. Have a plan to pay your monthlies.

Good news is I see a good bunch over 4.05%

As always just what I would do , your choice / decision / responsibility.

You are utterly out of your depth

Pull out
and just crack on paying off your London flat

Unless the extra 53k borrowing is on a very low interest rate you aren't going to find a high interest bank account rate that will pay you more than it will cost you to service the debt.
Banks will always intend to charge you more in interest on the money you borrow from them, than the interest they will pay you on savings you hold with them. This is how banks make money

If there is no early repayment charges then simplest thing is to repay. However I expect there will be.

So if you don't want to do landlording any more, look for the highest rate savings accounts you can on Martin Lewis website - you want one greater than 4.04 to break even - but remember you will be taxed if it is not an ISA at your income rate (40% as a higher rate tax payer) which will be hard to find right now.

Lock in the cash DONT spend and repay once erc time period is done. You may just luck out and break even as interest rates look to be going up soon.

Most important - you might have a lucky escape plan here due to world events. Don't sign any contracts in the future until you fully know the implications.

Tbh OP you sound like you are just determined to find a way to make money quick and turn the money you have into more money. If it was that easy everyone would do it - you run a significant risk of ending up with less, not more money, and having taken some of the equity out of your home your mortgage costs will be higher. With the state of the global economy and the situation in the middle East id put the money back in your flat and focus on paying down your mortgage and securing your home, not schemes to get rich quick.

Do you have the money already or not? It sounds strange to take out a mortgage advance to invest? To work out whether it’s worth it though you need to compare the rate of your mortgage vs the rate of interest/ investment return. If it’s not tax free you have to have interest of approx 7% to make up for a 4% mortgage or something like that - you’ll need to do the math.

If it’s just a mortgage offer and you haven’t received the money yet you can pull out any time. It’s hard to make money on a rental if you are full mortgaged op. Look into it more before you proceed.