Hi Trencher Tree,
It is not clear,based on the information provided, if your employer deducts your pension contributions from your pay before it is taxed.
If that is the case, you will have already received the tax relief you are entitled to, and you won't have to make any entries in the 'Paying into registered pension schemes' section of the SA100.
If not, please follow the detailed guidance in the SA100 notes.
How to fill in your tax return (2022)