What is "the payments and basic rate tax" for "Payments to registered pension schemes"?

I pay higher rate tax so would like to know what is the basic rate (20%) tax relief I need to add to, say, £700 paid to my pension? The pension provider adds £175 to the £700 so the total is £875 (875 x 0.8 = 700). However, for £700 post-tax, the pre-tax amount is £1166.6 given I pay higher rate tax. Does that mean I need to put in the box the £233.3 (1166.6 x 0.2 = 233.3) plus £700, i.e., £933.3 in the box?

Hi,

Under the ‘relief at source’ system, your pension provider claims basic rate tax relief (of 20%) on your personal contributions and adds that to your pension pot. Put the total amount in box 1 that is, your personal contributions paid to the scheme, plus the basic rate tax relief. Include any one-off payments you made in the year 2022 to 2023. One-off payments are payments made in the year to 5 April 2023 that you do not intend to repeat in the year to 5 April 2024. 

Thank you.