Hi mangoburger,
HMRC will automatically review the 2023/24 tax year once all the PAYE income details are received.
This includes taxable benefits from employers due in 6 July and untaxed intererst from banks & building societies.
It can take up to November to receive all the details but once reviewed if overpaid a calculation will be issued to you.
If you want to check if all the details have been received you can contact HMRC:
Income Tax: general enquiries
Thank you.