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HMRC internal manual

PAYE Manual

Employer returns: regulation 80 determinations: onus of proof

For ordinary time limit determinations it is the employer’s duty, on appeal, to show that the determination is wrong. For extended time limit determinations the onus is on the higher officer to show that tax was deliberately understated and or concealed.

You may have to use the PAYE tax calculator, go to GOV.UK/HMRC.