PAYE code adjustment for pension

Every year I make a pension contribution designed to ensure I do not pay higher rate tax. I do this at the end of the tax year so I have the best idea of my income. I did this once again in 2023/24 and, when submitting details after the end of the year to get a refund, I also asked for my 2024/25 PAYE code to be adjusted. This request in respect of the PAYE code was ignored so I submitted a request via my HMRC account to adjust the 2024/25 PAYE code. I have now received a letter back saying HMRC are unable to process my request as I need to write in and include evidence from my pension provider of the payment made this tax year. I haven't made the contribution yet and I won't until the end of the year - so how can I get this adjustment made? As PAYE is only ever an estimate, surely they need to be taking my best estimate of income/reliefs, unless they have reasonable cause to think I am lying. The pension contributions that I make each year are sizeable but HMRC can see I do this each year and have proof of the last contribution.

Hi,
To review this we will need to access your record.
You can contact HMRC to review at Income Tax: general enquiries
Thank you.