How to calculate CGT on overseas property

Hello, I am a resident in the UK since 2014. My parents have bought a flat in Poland, where I am from, around 2011. They gifted me the property 5 years ago and I sold it last month. I understand that I will be liable for CGT on the increase in value in the last 5 years. At the point of gifting the property, there was no valuation done. What method should I use to estimate the price of the flat at the point of gifting? When calculating the value, should I convert the price in PLN to GBP at the rate from 5 years ago? When do I need to report this by? Is this going to be part of my self-assessment for 2023-2024?

Hi

You will need to contact an estate agent to get valuations of similar properties that were sold at the same time the property was gifted to you.
All amounts must be converted to sterling to work out the gain and it will be in your 2023/24 tax return, due by 31/1/25.

Thank you