Incorrect P45 following TUPE

My employment was transferred under TUPE and I was immediately made redundant. The P45 issued by the new employer shows only pay and tax in respect of the Payment in Lieu of Notice. It does not include 4 months Pay and Tax in respect of the previous employment. It is likely that my total income for 23/24 will entitle me to a repayment of tax. How should I proceed?

Hi JonnieB,
When HMRC receive all the pay and tax from the previous employment if you have overpaid your tax HMRC would issue a tax code to your new job.
Which when operated would generate the tax refund.
If you think you are due a refund but not received, if you contact HMRC we can check this for you.
Income Tax: general enquiries
Thank you. 

Thank you for the reply. I am now retirned and it will be uncertain until April 5th whether a tax refund is required, I will follow up at that time.