No acknowledgement of paper CGT return?

My wife is unable to file a return online so back in January posted form "Capital Gains Tax on UK property return", recorded delivery (property sale was December 2023). She has had no acknowledgement nor has she received a tax bill. HMRC website says "You must report and pay any Capital Gains Tax due on UK residential property within 60 days of selling the property". Should she be worried? What can she do? many thanks

Hi

HMRC do not issue an acknowledgement. Once the return has been processed you will be issued with a letter to confirm the charge due and a payment reference.
You then have 14 days to make the payment. As long as the paper return was sent before the 60 day deadline and payment is made within the date on the letter (once received) no charges will be applied.

Thank you