P45 issues

[Wonderbug81]

I'm trying to file my self assessment form.

My main employer gave me a P45 when I left but the leaving date given on it falls in a different tax year to the payments (which were provided after I left).

Two contacts at HMRC (one a specialist apparently) plus my accountant has said this is wrong because it will show payment for a year when I wasn't employed by them and that I should also have had a P60 for the tax year I actually left but the employer has said they spoke to their HMRC contact who said no P60 was required for that year and the P45 is correct.

Any thoughts on what to do and/can anyone share the law/rules around this point?

Which tax year do the payments relate to?

Payments are for 2024/2025. I left in the previous tax year.

Just wondering if anyone can help with this?

Put on the tax form the income you received in the relevant tax year even if the P45 or P60 is wrong.
My son's employer got his P60 wrong this year - did not include previous employer's payments despite having all the details. The figure to go on should be what was paid in that tax year. If that is not clear look at bank statements and pay slips if P45 or P60 is wrong