Hi,
If you check your payslip and if the contributions are deducted before the tax is calculated then you already have received the relief on the contributions and you are not able to claim again.
If they are deducted from your net pay then you can make the claim at the PPR section on the tax return.
If you are not sure if the contributions are from gross or net pay then you can check with your payroll department or you can contact HMRC to check your record.
Contact HMRC
Thank you.