Disposal of buy to let

[devon]

I have just sold a “buy to let” property I have owned and rented out for 9 years.

I understand I am entitled to deduct from the gain the purchase and sale expenses and the current CGT allowance of £12000. is this correct?

Am I required to declare this gain immediately or can it await my self-assessment return for the 2019/2020 tax year due in April 2020

Any guidance would be gratefully received

[AGoodman]

Current rules still provide for the usual self assessment process and tax return.