CGT on main residence having moved back from overseas

I have recently moved back to UK and have now sold my house in UK and I am not sure of the position for Capital Gains Tax. I bought the property when I lived in the UK as my only and main residence and lived in it before I moved overseas in 2006. I lived and worked overseas for 18 years during which time I rented the property out. I have come back to UK to retire and have moved back into the Property as my main residence. I am now in the process of selling the property as I wish to downsize, but do not know what the Capital Gains position is: 1) Since the property was my main residence before I left UK and when I moved back to UK, is there a Capital Gains Tax to pay? Is 18 years too long to be considered "deemed absence" ? 2) If there is Capital Gains tax to pay, what date do I use to calculate the Capital Gain from? Is it the date when I moved overseas (2006) or is it 2015, the date at which overseas residents became liable for Capital Gains on UK residential property?

Hi,
You will be able to claim private residence relief for the period that the property was your main residence. You can see guidance here:
HS283 Private Residence Relief (2024)
There is also a calculator below, which leads on to the online capital gains service, which you can use to register for a capital gains account and report and pay the tax due, within 60 days of the completion date.
Tax when you sell property
Thank you.