Paying CGT when you don’t know your exact income

Dear HMRC, I am about to sell a BTL property and will need to pay CGT for me and my wife. We are both self employed and don’t know what our income will be for 2024/25 and haven’t filed for 2023/24 yet. In order to know what band we fall into, do we just estimate our income for 2024/25 on the CGT return and then pay the CGT amount based on this? When we come to filing the actual tax return for 2024/25 are any discrepancies then rectified when we know exactly what our income was? We have also declared a Form 17 to HMRC to split the income between myself and my wife (90% to her and 10% to me) so I assume we need to reflect the gain and the deductions in the same way? Many thanks for your help. Darren

Hi Darren Sharpe,
You are correct for all your  questions asked. 
Thank you.