Hi,
If you contribute to a pension scheme and the contribtions are dedcuted from your salary before the tax is calculated then you have already had the relief at source and would not be due further tax relief and as already deducted from your salary it would not be dedcuted again for the net adjusted income. Information on net adjusted income can be found here:
Personal Allowances: adjusted net income
If you receive a refund for pension contributions then the refund does not effect the net adjusted income
Thank you.