Lost PAYE forms
You cannot get a replacement P45.
Instead, your new employer may give you a ‘Starter Checklist’ or ask you for the relevant details about your finances to send to HM Revenue and Customs (HMRC).
You can get a replacement P60 from your employer.
You can usually get a copy of the P11D from your employer. If they cannot give you one, you can contact HMRC for a copy.