Self Assessment One-Off Payment Tax relief

I am a higher rate tax payer and have an occupation money purchase pension scheme, which receives a monthly contribution directly from my salary via the net pay arrangement method. For 2023/2024 I have some allowance remain and decided to make a one off payment to my private defined contribution pension scheme. The pension provider claimed 20% tax relief on my behalf, and I will have to claim the higher tax relief (20%) using the online self assessment (SA). However, I am struggling to fill in the SA without errors. There are 5 boxes under the pension section and only the second box (one off payment) is applicable, but if I leave the first box empty I get error. Could someone in the know advice? Thanks in advance.

Name removed admin .

Having re-read the descriptions I believe I would need to fill in first and second box, and in my case, both boxes contain the same figures. Hope this helps anyone who has the same querry.

Hi,
Box 1 of page TR4, is for payment made into a pension scheme that have only had tax relief of 20% claim by the pension provider.  
You gross up your pension payment (eg. (£1000/80)*100 = £1250) and declare the gross figure in box 1 of page TR4.  
You would also declare any one off payments in box 1.1.  Box 1.1 is additional information and is not part of a self assessment calculation.
Thank you.