What nationality are you? Can you tell me if you ever lived in the South Africa property and, if so, for how long. Has it been let at all? If so, for how long? What did it cost to buy? How much is it worth now?
Leave this with me while I draft my answer.
You should at section 5 of RDR1 here for the definition of domicile.
If you are UK domiciled, you are taxable on your worldwide income and gains with credit being given for foreign tax paid against the UK tax liability on the same income or gains. If you are not UK domiciled, you have the option to use the remittance basis of assessment which you can read about in section 9 of RDR1.
The gain will be about £70,702 (£213,422 - £122,720 - £20,000) if you take half the renovation costs into account. The first £11,100 will be tax free leaving you with a net taxable gain of £59,602.
There are two rates of CGT for residential property, 18% and 28%. The rate or combination of rates that you will pay will be dependent on the level of your income in the tax year you sell the property. In 2016/17, the current tax year, no more than £32,000 of the net taxable gain can be charged to CGT at 18%. If you let me know how much you earn, I will calculate the CGT for you.
I hope this helps but let me know if you have any further questions.
If you are UK domiciled, the gain will be taxable in the UK regardless of where the money ends up.
If your only income in 2016/17 is £20,000 (I'm assuming the £30,000 exemption for redundancy was used in 2015/16) and you sell the property in that tax year, then £23,000 of the net taxable gain will be taxed at 18% and the balance of £36,602 will be taxed at 28%. The CGT will be £14,388.56. Any CGT you have to pay in South Africa will be deductible from the UK tax liability.
You said your father contributed towards the total. By all means, claim the whole £40,000. HMRC may ask you to prove the improvement expenditure.
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